Xgu.ru теперь в Контакте  — приходите и подключайтесь.
Пока мы работаем над следующими видео, вы можете подключиться в Контакте. Познакомимся и обсудим новые страницы и ролики.

Vk-big.pngYoutube-big.jpeg

man/orig/zfs

Материал из Xgu.ru

Перейти к: навигация, поиск

Не указан параметр (1)


ZFS(8) FreeBSD System Manager's Manual ZFS(8)

Содержание

[править] NAME

    zfs — configures ZFS file systems

[править] SYNOPSIS

    zfs [-?]
    zfs create [-p] [-o property=value] ... filesystem
    zfs create [-ps] [-b blocksize] [-o property=value] ... -V size volume
    zfs destroy [-fnpRrv] filesystem|volume
    zfs destroy [-dnpRrv] snapshot[%snapname][,...]
    zfs snapshot [-r] [-o property=value] ...
        filesystem@snapname|volume@snapname
    zfs rollback [-rRf] snapshot
    zfs clone [-p] [-o property=value] ... snapshot filesystem|volume
    zfs promote clone-filesystem
    zfs rename filesystem|volume|snapshot filesystem|volume|snapshot
    zfs rename -p filesystem|volume filesystem|volume
    zfs rename -r snapshot snapshot
    zfs rename -u [-p] filesystem filesystem
    zfs list [-r|-d depth] [-H] [-o property[,...]] [-t type[,...]]
        [-s property] ... [-S property] ... filesystem|volume|snapshot
    zfs set property=value filesystem|volume|snapshot
    zfs get [-r|-d depth] [-Hp] [-o all | field[,...]] [-t type[,...]]
        [-s source[,...]] all | property[,...] filesystem|volume|snapshot
    zfs inherit [-rS] property filesystem|volume|snapshot
    zfs upgrade [-v]
    zfs upgrade [-r] [-V version] -a | filesystem
    zfs userspace [-niHp] [-o field[,...]] [-sS field] ... [-t type[,...]]
        filesystem|snapshot
    zfs groupspace [-niHp] [-o field[,...]] [-sS field] ... [-t type[,...]]
        filesystem|snapshot
    zfs mount
    zfs mount [-vO] [-o property[,...]] -a | filesystem
    zfs unmount [-f] -a | filesystem|mountpoint
    zfs share -a | filesystem
    zfs unshare -a | filesystem|mountpoint
    zfs send [-DnPpRrv] [-i snapshot | -I snapshot] snapshot
    zfs receive [-vnFu] filesystem|volume|snapshot
    zfs receive [-vnFu] [-d | -e] filesystem
    zfs allow filesystem|volume
    zfs allow [-ldug] everyone|user|group[,...] perm|@setname[,...]
        filesystem|volume
    zfs allow [-ld] -e perm|@setname[,...] filesystem|volume
    zfs allow -c perm|@setname[,...] filesystem|volume
    zfs allow -s @setname perm|@setname[,...] filesystem|volume
    zfs unallow [-rldug] everyone|user|group[,...] [perm|@setname[,...]]
        filesystem|volume
    zfs unallow [-rld] -e [perm|@setname[,...]] filesystem|volume
    zfs unallow [-r] -c [perm|@setname[,...]] filesystem|volume
    zfs unallow [-r] -s @setname perm|@setname[,...] filesystem|volume
    zfs hold [-r] tag snapshot ...
    zfs holds [-r] snapshot ...
    zfs release [-r] tag snapshot ...
    zfs diff [-FHt] snapshot [snapshot|filesystem]
    zfs jail jailid filesystem
    zfs unjail jailid filesystem

[править] DESCRIPTION

    The zfs command configures ZFS datasets within a ZFS storage pool, as
    described in zpool(8).  A dataset is identified by a unique path within
    the ZFS namespace. For example:
        pool/{filesystem,volume,snapshot}
    where the maximum length of a dataset name is MAXNAMELEN (256 bytes).
    A dataset can be one of the following:
    file system   A ZFS dataset of type filesystem can be mounted within the
                  standard system namespace and behaves like other file sys‐
                  tems. While ZFS file systems are designed to be POSIX com‐
                  pliant, known issues exist that prevent compliance in some
                  cases.  Applications that depend on standards conformance
                  might fail due to nonstandard behavior when checking file
                  system free space.
    volume        A logical volume exported as a raw or block device. This
                  type of dataset should only be used under special circum‐
                  stances. File systems are typically used in most environ‐
                  ments.
    snapshot      A read-only version of a file system or volume at a given
                  point in time. It is specified as filesystem@name or
                  volume@name.
  ZFS File System Hierarchy
    A ZFS storage pool is a logical collection of devices that provide space
    for datasets. A storage pool is also the root of the ZFS file system
    hierarchy.
    The root of the pool can be accessed as a file system, such as mounting
    and unmounting, taking snapshots, and setting properties. The physical
    storage characteristics, however, are managed by the zpool(8) command.
    See zpool(8) for more information on creating and administering pools.
  Snapshots
    A snapshot is a read-only copy of a file system or volume. Snapshots can
    be created extremely quickly, and initially consume no additional space
    within the pool. As data within the active dataset changes, the snapshot
    consumes more data than would otherwise be shared with the active
    dataset.
    Snapshots can have arbitrary names. Snapshots of volumes can be cloned or
    rolled back, but cannot be accessed independently.
    File system snapshots can be accessed under the .zfs/snapshot directory
    in the root of the file system. Snapshots are automatically mounted on
    demand and may be unmounted at regular intervals. The visibility of the
    .zfs directory can be controlled by the snapdir property.
  Clones
    A clone is a writable volume or file system whose initial contents are
    the same as another dataset. As with snapshots, creating a clone is
    nearly instantaneous, and initially consumes no additional space.
    Clones can only be created from a snapshot. When a snapshot is cloned, it
    creates an implicit dependency between the parent and child. Even though
    the clone is created somewhere else in the dataset hierarchy, the origi‐
    nal snapshot cannot be destroyed as long as a clone exists. The origin
    property exposes this dependency, and the destroy command lists any such
    dependencies, if they exist.
    The clone parent-child dependency relationship can be reversed by using
    the promote subcommand. This causes the "origin" file system to become a
    clone of the specified file system, which makes it possible to destroy
    the file system that the clone was created from.
  Mount Points
    Creating a ZFS file system is a simple operation, so the number of file
    systems per system is likely to be numerous. To cope with this, ZFS auto‐
    matically manages mounting and unmounting file systems without the need
    to edit the /etc/fstab file. All automatically managed file systems are
    mounted by ZFS at boot time.
    By default, file systems are mounted under /path, where path is the name
    of the file system in the ZFS namespace. Directories are created and
    destroyed as needed.
    A file system can also have a mount point set in the mountpoint property.
    This directory is created as needed, and ZFS automatically mounts the
    file system when the "zfs mount -a" command is invoked (without editing
    /etc/fstab).  The mountpoint property can be inherited, so if pool/home
    has a mount point of /home, then pool/home/user automatically inherits a
    mount point of /home/user.
    A file system mountpoint property of none prevents the file system from
    being mounted.
    If needed, ZFS file systems can also be managed with traditional tools
    (mount(8), umount(8), fstab(5)).  If a file system's mount point is set
    to legacy, ZFS makes no attempt to manage the file system, and the admin‐
    istrator is responsible for mounting and unmounting the file system.
  Jails
    A ZFS dataset can be attached to a jail by using the "zfs jail" subcom‐
    mand. You cannot attach a dataset to one jail and the children of the
    same dataset to another jails. To allow management of the dataset from
    within a jail, the jailed property has to be set. The quota property can‐
    not be changed from within a jail.
    A ZFS dataset can be detached from a jail using the "zfs unjail" subcom‐
    mand.
    After a dataset is attached to a jail and the jailed property is set, a
    jailed file system cannot be mounted outside the jail, since the jail
    administrator might have set the mount point to an unacceptable value.
  Deduplication
    Deduplication is the process for removing redundant data at the block-
    level, reducing the total amount of data stored. If a file system has the
    dedup property enabled, duplicate data blocks are removed synchronously.
    The result is that only unique data is stored and common components are
    shared among files.
  Native Properties
    Properties are divided into two types, native properties and user-defined
    (or "user") properties. Native properties either export internal statis‐
    tics or control ZFS behavior. In addition, native properties are either
    editable or read-only. User properties have no effect on ZFS behavior,
    but you can use them to annotate datasets in a way that is meaningful in
    your environment. For more information about user properties, see the
    "User Properties" section, below.
    Every dataset has a set of properties that export statistics about the
    dataset as well as control various behaviors. Properties are inherited
    from the parent unless overridden by the child. Some properties apply
    only to certain types of datasets (file systems, volumes, or snapshots).
    The values of numeric properties can be specified using human-readable
    suffixes (for example, k, KB, M, Gb, and so forth, up to Z for
    zettabyte). The following are all valid (and equal) specifications:
        1536M, 1.5g, 1.50GB
    The values of non-numeric properties are case sensitive and must be low‐
    ercase, except for mountpoint, sharenfs, and sharesmb.
    The following native properties consist of read-only statistics about the
    dataset. These properties can be neither set, nor inherited. Native prop‐
    erties apply to all dataset types unless otherwise noted.
    available
        The amount of space available to the dataset and all its children,
        assuming that there is no other activity in the pool. Because space
        is shared within a pool, availability can be limited by any number of
        factors, including physical pool size, quotas, reservations, or other
        datasets within the pool.
        This property can also be referred to by its shortened column name,
        avail.
    compressratio
        For non-snapshots, the compression ratio achieved for the used space
        of this dataset, expressed as a multiplier.  The used property
        includes descendant datasets, and, for clones, does not include the
        space shared with the origin snapshot.  For snapshots, the
        compressratio is the same as the refcompressratio property. Compres‐
        sion can be turned on by running: "zfs set compression=on dataset"
        The default value is off.
    creation
        The time this dataset was created.
    clones
        For snapshots, this property is a comma-separated list of filesystems
        or volumes which are clones of this snapshot.  The clones' origin
        property is this snapshot.  If the clones property is not empty, then
        this snapshot can not be destroyed (even with the -r or -f options).
    defer_destroy
        This property is on if the snapshot has been marked for deferred
        destroy by using the "zfs destroy -d" command. Otherwise, the prop‐
        erty is off.
    mounted
        For file systems, indicates whether the file system is currently
        mounted. This property can be either yes or no.
    origin
        For cloned file systems or volumes, the snapshot from which the clone
        was created. See also the clones property.
    referenced
        The amount of data that is accessible by this dataset, which may or
        may not be shared with other datasets in the pool. When a snapshot or
        clone is created, it initially references the same amount of space as
        the file system or snapshot it was created from, since its contents
        are identical.
        This property can also be referred to by its shortened column name,
        refer.
    refcompressratio
        The compression ratio achieved for the referenced space of this
        dataset, expressed as a multiplier.  See also the compressratio prop‐
        erty.
    type
        The type of dataset: filesystem, volume, or snapshot.
    used
        The amount of space consumed by this dataset and all its descendents.
        This is the value that is checked against this dataset's quota and
        reservation. The space used does not include this dataset's reserva‐
        tion, but does take into account the reservations of any descendent
        datasets. The amount of space that a dataset consumes from its par‐
        ent, as well as the amount of space that are freed if this dataset is
        recursively destroyed, is the greater of its space used and its
        reservation.
        When snapshots (see the "Snapshots" section) are created, their space
        is initially shared between the snapshot and the file system, and
        possibly with previous snapshots. As the file system changes, space
        that was previously shared becomes unique to the snapshot, and
        counted in the snapshot's space used. Additionally, deleting snap‐
        shots can increase the amount of space unique to (and used by) other
        snapshots.
        The amount of space used, available, or referenced does not take into
        account pending changes. Pending changes are generally accounted for
        within a few seconds. Committing a change to a disk using fsync(2) or
        O_SYNC does not necessarily guarantee that the space usage informa‐
        tion is updated immediately.
    usedby*
        The usedby* properties decompose the used properties into the various
        reasons that space is used. Specifically, used = usedbysnapshots +
        usedbydataset + usedbychildren + usedbyrefreservation.  These proper‐
        ties are only available for datasets created with ZFS pool version 13
        pools and higher.
    usedbysnapshots
        The amount of space consumed by snapshots of this dataset. In partic‐
        ular, it is the amount of space that would be freed if all of this
        dataset's snapshots were destroyed. Note that this is not simply the
        sum of the snapshots' used properties because space can be shared by
        multiple snapshots.
    usedbydataset
        The amount of space used by this dataset itself, which would be freed
        if the dataset were destroyed (after first removing any
        refreservation and destroying any necessary snapshots or descen‐
        dents).
    usedbychildren
        The amount of space used by children of this dataset, which would be
        freed if all the dataset's children were destroyed.
    usedbyrefreservation
        The amount of space used by a refreservation set on this dataset,
        which would be freed if the refreservation was removed.
    userused@user
        The amount of space consumed by the specified user in this dataset.
        Space is charged to the owner of each file, as displayed by "ls -l".
        The amount of space charged is displayed by "du" and "ls -s".  See
        the "zfs userspace" subcommand for more information.
        Unprivileged users can access only their own space usage. The root
        user, or a user who has been granted the userused privilege with "zfs
        allow", can access everyone's usage.
        The userused@... properties are not displayed by "zfs get all".  The
        user's name must be appended after the @ symbol, using one of the
        following forms:
          ·   POSIX name (for example, joe)
          ·   POSIX numeric ID (for example, 1001)
    userrefs
        This property is set to the number of user holds on this snapshot.
        User holds are set by using the "zfs hold" command.
    groupused@group
        The amount of space consumed by the specified group in this dataset.
        Space is charged to the group of each file, as displayed by ls -l.
        See the userused@user property for more information.
        Unprivileged users can only access their own groups' space usage. The
        root user, or a user who has been granted the groupused privilege
        with "zfs allow", can access all groups' usage.
    volblocksize=blocksize
        For volumes, specifies the block size of the volume. The blocksize
        cannot be changed once the volume has been written, so it should be
        set at volume creation time. The default blocksize for volumes is 8
        Kbytes. Any power of 2 from 512 bytes to 128 Kbytes is valid.
        This property can also be referred to by its shortened column name,
        volblock.
    written
        The amount of referenced space written to this dataset since the pre‐
        vious snapshot.
    written@snapshot
        The amount of referenced space written to this dataset since the
        specified snapshot.  This is the space that is referenced by this
        dataset but was not referenced by the specified snapshot.
        The snapshot may be specified as a short snapshot name (just the part
        after the @), in which case it will be interpreted as a snapshot in
        the same filesystem as this dataset. The snapshot may be a full snap‐
        shot name (filesystem@snapshot), which for clones may be a snapshot
        in the origin's filesystem (or the origin of the origin's filesystem,
        etc).
    The following native properties can be used to change the behavior of a
    ZFS dataset.
    aclinherit=discard | noallow | restricted | passthrough | passthrough-x
        Controls how ACL entries are inherited when files and directories are
        created. A file system with an aclinherit property of discard does
        not inherit any ACL entries. A file system with an aclinherit prop‐
        erty value of noallow only inherits inheritable ACL entries that
        specify "deny" permissions. The property value restricted (the
        default) removes the write_acl and write_owner permissions when the
        ACL entry is inherited. A file system with an aclinherit property
        value of passthrough inherits all inheritable ACL entries without any
        modifications made to the ACL entries when they are inherited. A file
        system with an aclinherit property value of passthrough-x has the
        same meaning as passthrough, except that the owner@, group@, and
        everyone@ ACEs inherit the execute permission only if the file cre‐
        ation mode also requests the execute bit.
        When the property value is set to passthrough, files are created with
        a mode determined by the inheritable ACEs. If no inheritable ACEs
        exist that affect the mode, then the mode is set in accordance to the
        requested mode from the application.
    aclmode=discard | groupmask | passthrough
        Controls how an ACL is modified during chmod(2).  A file system with
        an aclmode property of discard (the default) deletes all ACL entries
        that do not represent the mode of the file. An aclmode property of
        groupmask reduces permissions granted in all ALLOW entries found in
        the ACL such that they are no greater than the group permissions
        specified by chmod(2).  A file system with an aclmode property of
        passthrough indicates that no changes are made to the ACL other than
        creating or updating the necessary ACL entries to represent the new
        mode of the file or directory.
    atime=on | off
        Controls whether the access time for files is updated when they are
        read.  Turning this property off avoids producing write traffic when
        reading files and can result in significant performance gains, though
        it might confuse mailers and other similar utilities. The default
        value is on.
    canmount=on | off | noauto
        If this property is set to off, the file system cannot be mounted,
        and is ignored by "zfs mount -a".  Setting this property to off is
        similar to setting the mountpoint property to none, except that the
        dataset still has a normal mountpoint property, which can be inher‐
        ited. Setting this property to off allows datasets to be used solely
        as a mechanism to inherit properties. One example of setting
        canmount=off is to have two datasets with the same mountpoint, so
        that the children of both datasets appear in the same directory, but
        might have different inherited characteristics.
        When the noauto value is set, a dataset can only be mounted and
        unmounted explicitly. The dataset is not mounted automatically when
        the dataset is created or imported, nor is it mounted by the "zfs
        mount -a" command or unmounted by the "zfs umount -a" command.
        This property is not inherited.
    checksum=on | off | fletcher2 | fletcher4
        Controls the checksum used to verify data integrity. The default
        value is on, which automatically selects an appropriate algorithm
        (currently, fletcher4, but this may change in future releases). The
        value off disables integrity checking on user data. Disabling check‐
        sums is NOT a recommended practice.
    compression=on | off | lzjb | gzip | gzip-N | zle
        Controls the compression algorithm used for this dataset. The com‐
        pression algorithm is optimized for performance while providing
        decent data compression. Setting compression to on uses the lzjb com‐
        pression algorithm. The gzip compression algorithm uses the same com‐
        pression as the gzip(1) command. You can specify the gzip level by
        using the value gzip-N where N is an integer from 1 (fastest) to 9
        (best compression ratio). Currently, gzip is equivalent to gzip-6
        (which is also the default for gzip(1)).  The zle compression algo‐
        rithm compresses runs of zeros.
        This property can also be referred to by its shortened column name
        compress.  Changing this property affects only newly-written data.
    copies=1 | 2 | 3
        Controls the number of copies of data stored for this dataset. These
        copies are in addition to any redundancy provided by the pool, for
        example, mirroring or RAID-Z. The copies are stored on different
        disks, if possible. The space used by multiple copies is charged to
        the associated file and dataset, changing the used property and
        counting against quotas and reservations.
        Changing this property only affects newly-written data. Therefore,
        set this property at file system creation time by using the -o
        copies=N option.
    dedup=on | off | verify | sha256[,verify]
        Configures deduplication for a dataset. The default value is off.
        The default deduplication checksum is sha256 (this may change in the
        future).  When dedup is enabled, the checksum defined here overrides
        the checksum property. Setting the value to verify has the same
        effect as the setting sha256,verify.
        If set to verify, ZFS will do a byte-to-byte comparsion in case of
        two blocks having the same signature to make sure the block contents
        are identical.
    devices=on | off
        The devices property is currently not supported on FreeBSD.
    exec=on | off
        Controls whether processes can be executed from within this file sys‐
        tem. The default value is on.
    mlslabel=label | none
        The mlslabel property is currently not supported on FreeBSD.
    mountpoint=path | none | legacy
        Controls the mount point used for this file system. See the "Mount
        Points" section for more information on how this property is used.
        When the mountpoint property is changed for a file system, the file
        system and any children that inherit the mount point are unmounted.
        If the new value is legacy, then they remain unmounted. Otherwise,
        they are automatically remounted in the new location if the property
        was previously legacy or none, or if they were mounted before the
        property was changed. In addition, any shared file systems are
        unshared and shared in the new location.
    nbmand=on | off
        The nbmand property is currently not supported on FreeBSD.
    primarycache=all | none | metadata
        Controls what is cached in the primary cache (ARC). If this property
        is set to all, then both user data and metadata is cached. If this
        property is set to none, then neither user data nor metadata is
        cached. If this property is set to metadata, then only metadata is
        cached. The default value is all.
    quota=size | none
        Limits the amount of space a dataset and its descendents can consume.
        This property enforces a hard limit on the amount of space used. This
        includes all space consumed by descendents, including file systems
        and snapshots. Setting a quota on a descendent of a dataset that
        already has a quota does not override the ancestor's quota, but
        rather imposes an additional limit.
        Quotas cannot be set on volumes, as the volsize property acts as an
        implicit quota.
    userquota@user=size | none
        Limits the amount of space consumed by the specified user.  Similar
        to the refquota property, the userquota space calculation does not
        include space that is used by descendent datasets, such as snapshots
        and clones. User space consumption is identified by the
        userspace@user property.
        Enforcement of user quotas may be delayed by several seconds. This
        delay means that a user might exceed their quota before the system
        notices that they are over quota and begins to refuse additional
        writes with the EDQUOT error message. See the userspace subcommand
        for more information.
        Unprivileged users can only access their own groups' space usage. The
        root user, or a user who has been granted the userquota privilege
        with "zfs allow", can get and set everyone's quota.
        This property is not available on volumes, on file systems before
        version 4, or on pools before version 15. The userquota@... proper‐
        ties are not displayed by "zfs get all".  The user's name must be
        appended after the @ symbol, using one of the following forms:
          ·   POSIX name (for example, joe)
          ·   POSIX numeric ID (for example, 1001)
    groupquota@group=size | none
        Limits the amount of space consumed by the specified group. Group
        space consumption is identified by the userquota@user property.
        Unprivileged users can access only their own groups' space usage. The
        root user, or a user who has been granted the groupquota privilege
        with "zfs allow", can get and set all groups' quotas.
    readonly=on | off
        Controls whether this dataset can be modified. The default value is
        off.
    recordsize=size
        Specifies a suggested block size for files in the file system. This
        property is designed solely for use with database workloads that
        access files in fixed-size records.  ZFS automatically tunes block
        sizes according to internal algorithms optimized for typical access
        patterns.
        For databases that create very large files but access them in small
        random chunks, these algorithms may be suboptimal. Specifying a
        recordsize greater than or equal to the record size of the database
        can result in significant performance gains. Use of this property for
        general purpose file systems is strongly discouraged, and may
        adversely affect performance.
        The size specified must be a power of two greater than or equal to
        512 and less than or equal to 128 Kbytes.
        Changing the file system's recordsize affects only files created
        afterward; existing files are unaffected.
        This property can also be referred to by its shortened column name,
        recsize.
    refquota=size | none
        Limits the amount of space a dataset can consume. This property
        enforces a hard limit on the amount of space used. This hard limit
        does not include space used by descendents, including file systems
        and snapshots.
    refreservation=size | none
        The minimum amount of space guaranteed to a dataset, not including
        its descendents. When the amount of space used is below this value,
        the dataset is treated as if it were taking up the amount of space
        specified by refreservation.  The refreservation reservation is
        accounted for in the parent datasets' space used, and counts against
        the parent datasets' quotas and reservations.
        If refreservation is set, a snapshot is only allowed if there is
        enough free pool space outside of this reservation to accommodate the
        current number of "referenced" bytes in the dataset.
        This property can also be referred to by its shortened column name,
        refreserv.
    reservation=size | none
        The minimum amount of space guaranteed to a dataset and its descen‐
        dents. When the amount of space used is below this value, the dataset
        is treated as if it were taking up the amount of space specified by
        its reservation. Reservations are accounted for in the parent
        datasets' space used, and count against the parent datasets' quotas
        and reservations.
        This property can also be referred to by its shortened column name,
        reserv.
    secondarycache=all | none | metadata
        Controls what is cached in the secondary cache (L2ARC). If this prop‐
        erty is set to all, then both user data and metadata is cached. If
        this property is set to none, then neither user data nor metadata is
        cached. If this property is set to metadata, then only metadata is
        cached. The default value is all.
    setuid=on | off
        Controls whether the set-UID bit is respected for the file system.
        The default value is on.
    sharesmb=on | off | opts
        The sharesmb property has currently no effect o FreeBSD.
    sharenfs=on | off | opts
        Controls whether the file system is shared via NFS, and what options
        are used. A file system with a sharenfs property of off is managed
        the traditional way via exports(5).  Otherwise, the file system is
        automatically shared and unshared with the "zfs share" and "zfs
        unshare" commands. If the property is set to on no NFS export options
        are used. Otherwise, NFS export options are equivalent to the con‐
        tents of this property. The export options may be comma-separated.
        See exports(5) for a list of valid options.
        When the sharenfs property is changed for a dataset, the mountd(8)
        dameon is reloaded.
    logbias=latency | throughput
        Provide a hint to ZFS about handling of synchronous requests in this
        dataset.  If logbias is set to latency (the default), ZFS will use
        pool log devices (if configured) to handle the requests at low
        latency. If logbias is set to throughput, ZFS will not use configured
        pool log devices.  ZFS will instead optimize synchronous operations
        for global pool throughput and efficient use of resources.
    snapdir=hidden | visible
        Controls whether the .zfs directory is hidden or visible in the root
        of the file system as discussed in the "Snapshots" section. The
        default value is hidden.
    sync=standard | always | disabled
        Controls the behavior of synchronous requests (e.g.  fsync(2),
        O_DSYNC). This property accepts the following values:
            standard  This is the POSIX specified behavior of ensuring all
                      synchronous requests are written to stable storage and
                      all devices are flushed to ensure data is not cached by
                      device controllers (this is the default).
            always    All file system transactions are written and flushed
                      before their system calls return. This has a large per‐
                      formance penalty.
            disabled  Disables synchronous requests. File system transactions
                      are only committed to stable storage periodically. This
                      option will give the highest performance.  However, it
                      is very dangerous as ZFS would be ignoring the synchro‐
                      nous transaction demands of applications such as data‐
                      bases or NFS.  Administrators should only use this
                      option when the risks are understood.
    volsize=size
        For volumes, specifies the logical size of the volume. By default,
        creating a volume establishes a reservation of equal size. For stor‐
        age pools with a version number of 9 or higher, a refreservation is
        set instead. Any changes to volsize are reflected in an equivalent
        change to the reservation (or refreservation).  The volsize can only
        be set to a multiple of volblocksize, and cannot be zero.
        The reservation is kept equal to the volume's logical size to prevent
        unexpected behavior for consumers. Without the reservation, the vol‐
        ume could run out of space, resulting in undefined behavior or data
        corruption, depending on how the volume is used. These effects can
        also occur when the volume size is changed while it is in use (par‐
        ticularly when shrinking the size). Extreme care should be used when
        adjusting the volume size.
        Though not recommended, a "sparse volume" (also known as "thin provi‐
        sioning") can be created by specifying the -s option to the "zfs
        create -V" command, or by changing the reservation after the volume
        has been created. A "sparse volume" is a volume where the reservation
        is less then the volume size.  Consequently, writes to a sparse vol‐
        ume can fail with ENOSPC when the pool is low on space. For a sparse
        volume, changes to volsize are not reflected in the reservation.
    vscan=off | on
        The vscan property is currently not supported on FreeBSD.
    xattr=off | on
        The xattr property is currently not supported on FreeBSD.
    jailed=off | on
        Controls whether the dataset is managed from a jail. See the "Jails"
        section for more information. The default value is off.
    The following three properties cannot be changed after the file system is
    created, and therefore, should be set when the file system is created. If
    the properties are not set with the "zfs create" or zpool create com‐
    mands, these properties are inherited from the parent dataset. If the
    parent dataset lacks these properties due to having been created prior to
    these features being supported, the new file system will have the default
    values for these properties.
    casesensitivity=sensitive | insensitive | mixed
          The casesensitivity property is currently not supported on FreeBSD.
    normalization=none | formC | formD | formKC | formKD
          Indicates whether the file system should perform a unicode normal‐
          ization of file names whenever two file names are compared, and
          which normalization algorithm should be used. File names are always
          stored unmodified, names are normalized as part of any comparison
          process. If this property is set to a legal value other than none,
          and the utf8only property was left unspecified, the utf8only prop‐
          erty is automatically set to on.  The default value of the
          normalization property is none.  This property cannot be changed
          after the file system is created.
    utf8only=on | off
          Indicates whether the file system should reject file names that
          include characters that are not present in the UTF-8 character code
          set. If this property is explicitly set to off, the normalization
          property must either not be explicitly set or be set to none.  The
          default value for the utf8only property is off.  This property can‐
          not be changed after the file system is created.
    The casesensitivity, normalization, and utf8only properties are also new
    permissions that can be assigned to non-privileged users by using the ZFS
    delegated administration feature.
  Temporary Mount Point Properties
    When a file system is mounted, either through mount(8) for legacy mounts
    or the "zfs mount" command for normal file systems, its mount options are
    set according to its properties. The correlation between properties and
    mount options is as follows:
        PROPERTY    MOUNT OPTION
        atime       atime/noatime
        exec        exec/noexec
        readonly    ro/rw
        setuid      suid/nosuid
    In addition, these options can be set on a per-mount basis using the -o
    option, without affecting the property that is stored on disk. The values
    specified on the command line override the values stored in the dataset.
    These properties are reported as "temporary" by the "zfs get" command. If
    the properties are changed while the dataset is mounted, the new setting
    overrides any temporary settings.
  User Properties
    In addition to the standard native properties, ZFS supports arbitrary
    user properties. User properties have no effect on ZFS behavior, but
    applications or administrators can use them to annotate datasets (file
    systems, volumes, and snapshots).
    User property names must contain a colon (:) character to distinguish
    them from native properties. They may contain lowercase letters, numbers,
    and the following punctuation characters: colon (:), dash (-), period (.)
    and underscore (_).  The expected convention is that the property name is
    divided into two portions such as module:property, but this namespace is
    not enforced by ZFS.  User property names can be at most 256 characters,
    and cannot begin with a dash (-).
    When making programmatic use of user properties, it is strongly suggested
    to use a reversed DNS domain name for the module component of property
    names to reduce the chance that two independently-developed packages use
    the same property name for different purposes. Property names beginning
    with com.sun are reserved for use by Sun Microsystems.
    The values of user properties are arbitrary strings, are always inher‐
    ited, and are never validated. All of the commands that operate on prop‐
    erties ("zfs list", "zfs get", "zfs set" and so forth) can be used to
    manipulate both native properties and user properties. Use the "zfs
    inherit" command to clear a user property. If the property is not defined
    in any parent dataset, it is removed entirely. Property values are lim‐
    ited to 1024 characters.

[править] SUBCOMMANDS

    All subcommands that modify state are logged persistently to the pool in
    their original form.
    zfs [-?]
        Displays a help message.
    zfs create [-p] [-o property=value] ... filesystem
        Creates a new ZFS file system. The file system is automatically
        mounted according to the mountpoint property inherited from the par‐
        ent.
        -p      Creates all the non-existing parent datasets. Datasets cre‐
                ated in this manner are automatically mounted according to
                the mountpoint property inherited from their parent. Any
                property specified on the command line using the -o option is
                ignored. If the target filesystem already exists, the opera‐
                tion completes successfully.
        -o property=value
                Sets the specified property as if the command "zfs set
                property=value" was invoked at the same time the dataset was
                created. Any editable ZFS property can also be set at cre‐
                ation time. Multiple -o options can be specified. An error
                results if the same property is specified in multiple -o
                options.
    zfs create [-ps] [-b blocksize] [-o property=value] ... -V size volume
        Creates a volume of the given size. The volume is exported as a block
        device in /dev/zvol/path, where path is the name of the volume in the
        ZFS namespace. The size represents the logical size as exported by
        the device. By default, a reservation of equal size is created.
        size is automatically rounded up to the nearest 128 Kbytes to ensure
        that the volume has an integral number of blocks regardless of
        blocksize.
        -p      Creates all the non-existing parent datasets. Datasets cre‐
                ated in this manner are automatically mounted according to
                the mountpoint property inherited from their parent. Any
                property specified on the command line using the -o option is
                ignored. If the target filesystem already exists, the opera‐
                tion completes successfully.
        -s      Creates a sparse volume with no reservation. See volsize in
                the "Native Properties" section for more information about
                sparse volumes.
        -b blocksize
                Equivalent to -o volblocksize=blocksize.  If this option is
                specified in conjunction with -o volblocksize, the resulting
                behavior is undefined.
        -o property=value
                Sets the specified property as if the "zfs set
                property=value" command was invoked at the same time the
                dataset was created. Any editable ZFS property can also be
                set at creation time. Multiple -o options can be specified.
                An error results if the same property is specified in multi‐
                ple -o options.
    zfs destroy [-fnpRrv] filesystem|volume
        Destroys the given dataset. By default, the command unshares any file
        systems that are currently shared, unmounts any file systems that are
        currently mounted, and refuses to destroy a dataset that has active
        dependents (children or clones).
        -r      Recursively destroy all children.
        -R      Recursively destroy all dependents, including cloned file
                systems outside the target hierarchy.
        -f      Force an unmount of any file systems using the "zfs unmount
                -f" command. This option has no effect on non-file systems or
                unmounted file systems.
        -n      Do a dry-run ("No-op") deletion. No data will be deleted.
                This is useful in conjunction with the -v or -p flags to
                determine what data would be deleted.
        -p      Print machine-parsable verbose information about the deleted
                data.
        -v      Print verbose information about the deleted data.
        Extreme care should be taken when applying either the -r or the -R
        options, as they can destroy large portions of a pool and cause unex‐
        pected behavior for mounted file systems in use.
    zfs destroy [-dnpRrv] snapshot[%snapname][,...]
        The given snapshots are destroyed immediately if and only if the "zfs
        destroy" command without the -d option would have destroyed it. Such
        immediate destruction would occur, for example, if the snapshot had
        no clones and the user-initiated reference count were zero.
        If a snapshot does not qualify for immediate destruction, it is
        marked for deferred deletion. In this state, it exists as a usable,
        visible snapshot until both of the preconditions listed above are
        met, at which point it is destroyed.
        An inclusive range of snapshots may be specified by separating the
        first and last snapshots with a percent sign (%).  The first and/or
        last snapshots may be left blank, in which case the filesystem's old‐
        est or newest snapshot will be implied.
        Multiple snapshots (or ranges of snapshots) of the same filesystem or
        volume may be specified in a comma-separated list of snapshots.  Only
        the snapshot's short name (the part after the @) should be specified
        when using a range or comma-separated list to identify multiple snap‐
        shots.
        -r      Destroy (or mark for deferred deletion) all snapshots with
                this name in descendent file systems.
        -R      Recursively destroy all dependents.
        -n      Do a dry-run ("No-op") deletion. No data will be deleted.
                This is useful in conjunction with the -v or -p flags to
                determine what data would be deleted.
        -p      Print machine-parsable verbose information about the deleted
                data.
        -v      Print verbose information about the deleted data.
        -d      Defer snapshot deletion.
        Extreme care should be taken when applying either the -r or the -R
        options, as they can destroy large portions of a pool and cause unex‐
        pected behavior for mounted file systems in use.
    zfs snapshot [-r] [-o property=value] ...
        filesystem@snapname|volume@snapname
        Creates a snapshot with the given name. All previous modifications by
        successful system calls to the file system are part of the snapshot.
        See the "Snapshots" section for details.
        -r      Recursively create snapshots of all descendent datasets.
                Snapshots are taken atomically, so that all recursive snap‐
                shots correspond to the same moment in time.
        -o property=value
                Sets the specified property; see "zfs create" for details.
    zfs rollback [-rRf] snapshot
        Roll back the given dataset to a previous snapshot. When a dataset is
        rolled back, all data that has changed since the snapshot is dis‐
        carded, and the dataset reverts to the state at the time of the snap‐
        shot. By default, the command refuses to roll back to a snapshot
        other than the most recent one. In order to do so, all intermediate
        snapshots must be destroyed by specifying the -r option.
        -r      Recursively destroy any snapshots more recent than the one
                specified.
        -R      Recursively destroy any more recent snapshots, as well as any
                clones of those snapshots.
        -f      Used with the -R option to force an unmount of any clone file
                systems that are to be destroyed.
    zfs clone [-p] [-o property=value] ... snapshot filesystem|volume
        Creates a clone of the given snapshot. See the "Clones" section for
        details. The target dataset can be located anywhere in the ZFS hier‐
        archy, and is created as the same type as the original.
        -p      Creates all the non-existing parent datasets. Datasets cre‐
                ated in this manner are automatically mounted according to
                the mountpoint property inherited from their parent. If the
                target filesystem or volume already exists, the operation
                completes successfully.
        -o property=value
                Sets the specified property; see "zfs create" for details.
    zfs promote clone-filesystem
        Promotes a clone file system to no longer be dependent on its "ori‐
        gin" snapshot. This makes it possible to destroy the file system that
        the clone was created from. The clone parent-child dependency rela‐
        tionship is reversed, so that the origin file system becomes a clone
        of the specified file system.
        The snapshot that was cloned, and any snapshots previous to this
        snapshot, are now owned by the promoted clone. The space they use
        moves from the origin file system to the promoted clone, so enough
        space must be available to accommodate these snapshots. No new space
        is consumed by this operation, but the space accounting is adjusted.
        The promoted clone must not have any conflicting snapshot names of
        its own. The rename subcommand can be used to rename any conflicting
        snapshots.
    zfs rename filesystem|volume|snapshot filesystem|volume|snapshot
    zfs rename -p filesystem|volume filesystem|volume
    zfs rename -u [-p] filesystem filesystem
        Renames the given dataset. The new target can be located anywhere in
        the ZFS hierarchy, with the exception of snapshots. Snapshots can
        only be renamed within the parent file system or volume. When renam‐
        ing a snapshot, the parent file system of the snapshot does not need
        to be specified as part of the second argument. Renamed file systems
        can inherit new mount points, in which case they are unmounted and
        remounted at the new mount point.
        -p      Creates all the nonexistent parent datasets. Datasets created
                in this manner are automatically mounted according to the
                mountpoint property inherited from their parent.
        -u      Do not remount file systems during rename. If a file system's
                mountpoint property is set to legacy or none, file system is
                not unmounted even if this option is not given.
    zfs rename -r snapshot snapshot
        Recursively rename the snapshots of all descendent datasets. Snap‐
        shots are the only dataset that can be renamed recursively.
    zfs list [-r|-d depth] [-H] [-o property[,...]] [-t type[,...]] [-s
        property] ... [-S property] ... filesystem|volume|snapshot
        Lists the property information for the given datasets in tabular
        form. If specified, you can list property information by the absolute
        pathname or the relative pathname. By default, all file systems and
        volumes are displayed.  Snapshots are displayed if the listsnaps
        property is on (the default is off).  The following fields are dis‐
        played, name, used, available, referenced, mountpoint.
        -r      Recursively display any children of the dataset on the com‐
                mand line.
        -d depth
                Recursively display any children of the dataset, limiting the
                recursion to depth.  A depth of 1 will display only the
                dataset and its direct children.
        -H      Used for scripting mode. Do not print headers and separate
                fields by a single tab instead of arbitrary white space.
        -o property[,...]
                A comma-separated list of properties to display. The property
                must be:
                  ·   One of the properties described in the "Native
                      Properties" section
                  ·   A user property
                  ·   The value name to display the dataset name
                  ·   The value space to display space usage properties on
                      file systems and volumes. This is a shortcut for speci‐
                      fying -o
                      name,avail,used,usedsnap,usedds,usedrefreserv,usedchild
                      -t filesystem,volume syntax.
        -t type[,...]
                A comma-separated list of types to display, where type is one
                of filesystem, snapshot, volume, or all.  For example, speci‐
                fying -t snapshot displays only snapshots.
        -s property
                A property for sorting the output by column in ascending
                order based on the value of the property. The property must
                be one of the properties described in the "Properties" sec‐
                tion, or the special value name to sort by the dataset name.
                Multiple properties can be specified at one time using multi‐
                ple -s property options. Multiple -s options are evaluated
                from left to right in decreasing order of importance.
                The following is a list of sorting criteria:
                  ·   Numeric types sort in numeric order.
                  ·   String types sort in alphabetical order.
                  ·   Types inappropriate for a row sort that row to the lit‐
                      eral bottom, regardless of the specified ordering.
                  ·   If no sorting options are specified the existing behav‐
                      ior of "zfs list" is preserved.
        -S property
                Same as the -s option, but sorts by property in descending
                order.
    zfs set property=value filesystem|volume|snapshot
        Sets the property to the given value for each dataset. Only some
        properties can be edited. See the "Properties" section for more
        information on what properties can be set and acceptable values.
        Numeric values can be specified as exact values, or in a human-read‐
        able form with a suffix of B, K, M, G, T, P, E, Z (for bytes, kilo‐
        bytes, megabytes, gigabytes, terabytes, petabytes, exabytes, or
        zettabytes, respectively). User properties can be set on snapshots.
        For more information, see the "User Properties" section.
    zfs get [-r|-d depth] [-Hp] [-o all | field[,...]] [-t type[,...]] [-s
        source[,...]] all | property[,...] filesystem|volume|snapshot
        Displays properties for the given datasets. If no datasets are speci‐
        fied, then the command displays properties for all datasets on the
        system. For each property, the following columns are displayed:
              name      Dataset name
              property  Property name
              value     Property value
              source    Property source. Can either be local, default, tempo‐
                        rary, inherited, or none (-).
        All columns except the RECEIVED column are displayed by default. The
        columns to display can be specified by using the -o option. This com‐
        mand takes a comma-separated list of properties as described in the
        "Native Properties" and "User Properties" sections.
        The special value all can be used to display all properties that
        apply to the given dataset's type (filesystem, volume, or snapshot).
        -r      Recursively display properties for any children.
        -d depth
                Recursively display any children of the dataset, limiting the
                recursion to depth.  A depth of 1 will display only the
                dataset and its direct children.
        -H      Display output in a form more easily parsed by scripts. Any
                headers are omitted, and fields are explicitly separated by a
                single tab instead of an arbitrary amount of space.
        -p      Display numbers in parseable (exact) values.
        -o all | field[,...]
                A comma-separated list of columns to display. Supported val‐
                ues are name,property,value,received,source.  Default values
                are name,property,value,source.  The keyword all specifies
                all columns.
        -t type[,...]
                A comma-separated list of types to display, where type is one
                of filesystem, snapshot, volume, or all.  For example, speci‐
                fying -t snapshot displays only snapshots.
        -s source[,...]
                A comma-separated list of sources to display. Those proper‐
                ties coming from a source other than those in this list are
                ignored. Each source must be one of the following:
                local,default,inherited,temporary,received,none.  The default
                value is all sources.
    zfs inherit [-rS] property filesystem|volume|snapshot
        Clears the specified property, causing it to be inherited from an
        ancestor. If no ancestor has the property set, then the default value
        is used. See the "Properties" section for a listing of default val‐
        ues, and details on which properties can be inherited.
        -r      Recursively inherit the given property for all children.
        -S      For properties with a received value, revert to this value.
                This flag has no effect on properties that do not have a
                received value.
    zfs upgrade [-v]
        Displays a list of file systems that are not the most recent version.
        -v      Displays ZFS filesystem versions supported by the current
                software. The current ZFS filesystem version and all previous
                supported versions are displayed, along with an explanation
                of the features provided with each version.
    zfs upgrade [-r] [-V version] -a | filesystem
        Upgrades file systems to a new on-disk version. Once this is done,
        the file systems will no longer be accessible on systems running
        older versions of the software.  "zfs send" streams generated from
        new snapshots of these file systems cannot be accessed on systems
        running older versions of the software.
        In general, the file system version is independent of the pool ver‐
        sion. See zpool(8) for information on the zpool upgrade command.
        In some cases, the file system version and the pool version are
        interrelated and the pool version must be upgraded before the file
        system version can be upgraded.
        -r      Upgrade the specified file system and all descendent file
                systems.
        -V version
                Upgrade to the specified version.  If the -V flag is not
                specified, this command upgrades to the most recent version.
                This option can only be used to increase the version number,
                and only up to the most recent version supported by this
                software.
        -a      Upgrade all file systems on all imported pools.
        filesystem
                Upgrade the specified file system.
    zfs userspace [-niHp] [-o field[,...]] [-sS field] ... [-t type[,...]]
        filesystem|snapshot
        Displays space consumed by, and quotas on, each user in the specified
        filesystem or snapshot. This corresponds to the userused@user and
        userquota@user properties.
        -n      Print numeric ID instead of user/group name.
        -H      Do not print headers, use tab-delimited output.
        -p      Use exact (parseable) numeric output.
        -o field[,...]
                Display only the specified fields from the following set,
                type,name,used,quota.  The default is to display all fields.
        -s field
                Sort output by this field. The -s and -S flags may be speci‐
                fied multiple times to sort first by one field, then by
                another. The default is -s type -s name.
        -S field
                Sort by this field in reverse order. See -s.
        -t type[,...]
                Print only the specified types from the following set,
                all,posixuser,smbuser,posixgroup,smbgroup.
                The default is -t posixuser,smbuser.
                The default can be changed to include group types.
        -i      Translate SID to POSIX ID. This flag has currently no effect
                on FreeBSD.
    zfs groupspace [-niHp] [-o field[,...]] [-sS field] ... [-t type[,...]]
        filesystem|snapshot
        Displays space consumed by, and quotas on, each group in the speci‐
        fied filesystem or snapshot. This subcommand is identical to "zfs
        userspace", except that the default types to display are -t
        posixgroup,smbgroup.
    zfs mount
        Displays all ZFS file systems currently mounted.
        -f
    zfs mount [-vO] [-o property[,...]] -a | filesystem
        Mounts ZFS file systems.
        -v      Report mount progress.
        -O      Perform an overlay mount. Overlay mounts are not supported on
                FreeBSD.
        -o property[,...]
                An optional, comma-separated list of mount options to use
                temporarily for the duration of the mount. See the "Temporary
                Mount Point Properties" section for details.
        -a      Mount all available ZFS file systems.  This command may be
                executed on FreeBSD system startup by /etc/rc.d/zfs.  For
                more information, see variable zfs_enable in rc.conf(5).
        filesystem
                Mount the specified filesystem.
    zfs unmount [-f] -a | filesystem|mountpoint
        Unmounts currently mounted ZFS file systems.
        -f      Forcefully unmount the file system, even if it is currently
                in use.
        -a      Unmount all available ZFS file systems.
        filesystem | mountpoint
                Unmount the specified filesystem. The command can also be
                given a path to a ZFS file system mount point on the system.
    zfs share -a | filesystem
        Shares ZFS file systems that have the sharenfs property set.
        -a      Share all ZFS file systems that have the sharenfs property
                set.  This command may be executed on FreeBSD system startup
                by /etc/rc.d/zfs.  For more information, see variable
                zfs_enable in rc.conf(5).
        filesystem
                Share the specified filesystem according to the sharenfs
                property. File systems are shared when the sharenfs property
                is set.
    zfs unshare -a | filesystem|mountpoint
        Unshares ZFS file systems that have the sharenfs property set.
        -a      Unshares ZFS file systems that have the sharenfs property
                set.  This command may be executed on FreeBSD system shutdown
                by /etc/rc.d/zfs.  For more information, see variable
                zfs_enable in rc.conf(5).
        filesystem | mountpoint
                Unshare the specified filesystem. The command can also be
                given a path to a ZFS file system shared on the system.
    zfs send [-DnPpRrv] [-i snapshot | -I snapshot] snapshot
        Creates a stream representation of the last snapshot argument (not
        part of -i or -I) which is written to standard output. The output can
        be redirected to a file or to a different system (for example, using
        ssh(1)).  By default, a full stream is generated.
        -i snapshot
                Generate an incremental stream from the -i snapshot to the
                last snapshot.  The incremental source (the -i snapshot) can
                be specified as the last component of the snapshot name (for
                example, the part after the @), and it is assumed to be from
                the same file system as the last snapshot.
                If the destination is a clone, the source may be the origin
                snapshot, which must be fully specified (for example,
                pool/fs@origin, not just @origin).
        -I snapshot
                Generate a stream package that sends all intermediary snap‐
                shots from the -I snapshot to the last snapshot.  For exam‐
                ple, -I @a fs@d is similar to -i @a fs@b; -i @b fs@c; -i @c
                fs@d.  The incremental source snapshot may be specified as
                with the -i option.
        -R      Generate a replication stream package, which will replicate
                the specified filesystem, and all descendent file systems, up
                to the named snapshot. When received, all properties, snap‐
                shots, descendent file systems, and clones are preserved.
                If the -i or -I flags are used in conjunction with the -R
                flag, an incremental replication stream is generated. The
                current values of properties, and current snapshot and file
                system names are set when the stream is received. If the -F
                flag is specified when this stream is received, snapshots and
                file systems that
                 do not exist on the sending side are destroyed.
        -D      Generate a deduplicated stream. Blocks which would have been
                sent multiple times in the send stream will only be sent
                once.  The receiving system must also support this feature to
                receive a deduplicated stream.  This flag can be used regard‐
                less of the dataset's dedup property, but performance will be
                much better if the filesystem uses a dedup-capable checksum
                (eg.  sha256).
        -r      Recursively send all descendant snapshots.  This is similar
                to the -R flag, but information about deleted and renamed
                datasets is not included, and property information is only
                included if the -p flag is specified.
        -p      Include the dataset's properties in the stream. This flag is
                implicit when -R is specified. The receiving system must also
                support this feature.
        -n      Do a dry-run ("No-op") send.  Do not generate any actual send
                data.  This is useful in conjunction with the -v or -P flags
                to determine what data will be sent.
        -P      Print machine-parsable verbose information about the stream
                package generated.
        -v      Print verbose information about the stream package generated.
        The format of the stream is committed. You will be able to receive
        your streams on future versions of ZFS.
    zfs receive [-vnFu] filesystem|volume|snapshot
    zfs receive [-vnFu] [-d | -e] filesystem
        Creates a snapshot whose contents are as specified in the stream pro‐
        vided on standard input. If a full stream is received, then a new
        file system is created as well. Streams are created using the "zfs
        send" subcommand, which by default creates a full stream.  "zfs recv"
        can be used as an alias for "zfs receive".
        If an incremental stream is received, then the destination file sys‐
        tem must already exist, and its most recent snapshot must match the
        incremental stream's source. For zvols, the destination device link
        is destroyed and recreated, which means the zvol cannot be accessed
        during the receive operation.
        When a snapshot replication package stream that is generated by using
        the "zfs send -R" command is received, any snapshots that do not
        exist on the sending location are destroyed by using the "zfs destroy
        -d" command.
        The name of the snapshot (and file system, if a full stream is
        received) that this subcommand creates depends on the argument type
        and the -d or -e option.
        If the argument is a snapshot name, the specified snapshot is cre‐
        ated. If the argument is a file system or volume name, a snapshot
        with the same name as the sent snapshot is created within the speci‐
        fied filesystem or volume.  If the -d or -e option is specified, the
        snapshot name is determined by appending the sent snapshot's name to
        the specified filesystem.  If the -d option is specified, all but the
        pool name of the sent snapshot path is appended (for example, b/c@1
        appended from sent snapshot a/b/c@1), and if the -e option is speci‐
        fied, only the tail of the sent snapshot path is appended (for exam‐
        ple, c@1 appended from sent snapshot a/b/c@1).  In the case of -d,
        any file systems needed to replicate the path of the sent snapshot
        are created within the specified file system.
        -d      Use the full sent snapshot path without the first element
                (without pool name) to determine the name of the new snapshot
                as described in the paragraph above.
        -e      Use only the last element of the sent snapshot path to deter‐
                mine the name of the new snapshot as described in the para‐
                graph above.
        -u      File system that is associated with the received stream is
                not mounted.
        -v      Print verbose information about the stream and the time
                required to perform the receive operation.
        -n      Do not actually receive the stream. This can be useful in
                conjunction with the -v option to verify the name the receive
                operation would use.
        -F      Force a rollback of the file system to the most recent snap‐
                shot before performing the receive operation. If receiving an
                incremental replication stream (for example, one generated by
                "zfs send -R -Fi -iI"), destroy snapshots and file systems
                that do not exist on the sending side.
    zfs allow filesystem|volume
        Displays permissions that have been delegated on the specified
        filesystem or volume. See the other forms of "zfs allow" for more
        information.
    zfs allow [-ldug] everyone|user|group[,...] perm|@setname[,...]
        filesystem|volume
    zfs allow [-ld] -e perm|@setname[,...] filesystem|volume
        Delegates ZFS administration permission for the file systems to non-
        privileged users.
        [-ug] everyone|user|group[,...]
                Specifies to whom the permissions are delegated. Multiple
                entities can be specified as a comma-separated list. If nei‐
                ther of the -ug options are specified, then the argument is
                interpreted preferentially as the keyword "everyone", then as
                a user name, and lastly as a group name. To specify a user or
                group named "everyone", use the -u or -g options. To specify
                a group with the same name as a user, use the -g option.
        [-e] perm|@setname[,...]
                Specifies that the permissions be delegated to "everyone".
                Multiple permissions may be specified as a comma-separated
                list. Permission names are the same as ZFS subcommand and
                property names. See the property list below. Property set
                names, which begin with an at sign (@), may be specified. See
                the -s form below for details.
        [-ld] filesystem|volume
                Specifies where the permissions are delegated. If neither of
                the -ld options are specified, or both are, then the permis‐
                sions are allowed for the file system or volume, and all of
                its descendents. If only the -l option is used, then is
                allowed "locally" only for the specified file system.  If
                only the -d option is used, then is allowed only for the
                descendent file systems.
        Permissions are generally the ability to use a ZFS subcommand or
        change a ZFS property. The following permissions are available:
            NAME              TYPE          NOTES
            allow             subcommand    Must also have the permission
                                            that is being allowed
            clone             subcommand    Must also have the 'create'
                                            ability and 'mount' ability in
                                            the origin file system
            create            subcommand    Must also have the 'mount'
                                            ability
            destroy           subcommand    Must also have the 'mount'
                                            ability
            hold              subcommand    Allows adding a user hold to a
                                            snapshot
            mount             subcommand    Allows mount/umount of ZFS
                                            datasets
            promote           subcommand    Must also have the 'mount' and
                                            'promote' ability in the origin
                                            file system
            receive           subcommand    Must also have the 'mount' and
                                            'create' ability
            release           subcommand    Allows releasing a user hold
                                            which might destroy the snapshot
            rename            subcommand    Must also have the 'mount' and
                                            'create' ability in the new
                                            parent
            rollback          subcommand    Must also have the 'mount'
                                            ability
            send              subcommand
            share             subcommand    Allows sharing file systems over
                                            the NFS protocol
            snapshot          subcommand    Must also have the 'mount'
                                            ability
            groupquota        other         Allows accessing any
                                            groupquota@... property
            groupused         other         Allows reading any groupused@...
                                            property
            userprop          other         Allows changing any user property
            userquota         other         Allows accessing any
                                            userquota@... property
            userused          other         Allows reading any userused@...
                                            property
            aclinherit        property
            aclmode           property
            atime             property
            canmount          property
            casesensitivity   property
            checksum          property
            compression       property
            copies            property
            dedup             property
            devices           property
            exec              property
            logbias           property
            jailed            property
            mlslabel          property
            mountpoint        property
            nbmand            property
            normalization     property
            primarycache      property
            quota             property
            readonly          property
            recordsize        property
            refquota          property
            refreservation    property
            reservation       property
            secondarycache    property
            setuid            property
            sharenfs          property
            sharesmb          property
            snapdir           property
            sync              property
            utf8only          property
            version           property
            volblocksize      property
            volsize           property
            vscan             property
            xattr             property
    zfs allow -c perm|@setname[,...] filesystem|volume
        Sets "create time" permissions. These permissions are granted
        (locally) to the creator of any newly-created descendent file system.
    zfs allow -s @setname perm|@setname[,...] filesystem|volume
        Defines or adds permissions to a permission set. The set can be used
        by other "zfs allow" commands for the specified file system and its
        descendents. Sets are evaluated dynamically, so changes to a set are
        immediately reflected. Permission sets follow the same naming
        restrictions as ZFS file systems, but the name must begin with an "at
        sign" (@), and can be no more than 64 characters long.
    zfs unallow [-rldug] everyone|user|group[,...] [perm|@setname[,...]]
        filesystem|volume
    zfs unallow [-rld] -e [perm|@setname[,...]] filesystem|volume
    zfs unallow [-r] -c [perm|@setname[,...]] filesystem|volume
        Removes permissions that were granted with the "zfs allow" command.
        No permissions are explicitly denied, so other permissions granted
        are still in effect. For example, if the permission is granted by an
        ancestor. If no permissions are specified, then all permissions for
        the specified user, group, or everyone are removed. Specifying
        "everyone" (or using the -e option) only removes the permissions that
        were granted to "everyone", not all permissions for every user and
        group. See the "zfs allow" command for a description of the -ldugec
        options.
        -r      Recursively remove the permissions from this file system and
                all descendents.
    zfs unallow [-r] -s @setname perm|@setname[,...] filesystem|volume
        Removes permissions from a permission set. If no permissions are
        specified, then all permissions are removed, thus removing the set
        entirely.
    zfs hold [-r] tag snapshot ...
        Adds a single reference, named with the tag argument, to the speci‐
        fied snapshot or snapshots. Each snapshot has its own tag namespace,
        and tags must be unique within that space.
        If a hold exists on a snapshot, attempts to destroy that snapshot by
        using the "zfs destroy" command returns EBUSY.
        -r      Specifies that a hold with the given tag is applied recur‐
                sively to the snapshots of all descendent file systems.
    zfs holds [-r] snapshot ...
        Lists all existing user references for the given snapshot or snap‐
        shots.
        -r      Lists the holds that are set on the named descendent snap‐
                shots, in addition to listing the holds on the named snap‐
                shot.
    zfs release [-r] tag snapshot ...
        Removes a single reference, named with the tag argument, from the
        specified snapshot or snapshots. The tag must already exist for each
        snapshot.
        -r      Recursively releases a hold with the given tag on the snap‐
                shots of all descendent file systems.
    zfs diff [-FHt] snapshot [snapshot|filesystem]
        Describes differences between a snapshot and a successor dataset. The
        successor dataset can be a later snapshot or the current filesystem.
        The changed files are displayed including the change type. The change
        type is displayed useing a single character. If a file or directory
        was renamed, the old and the new names are displayed.
        The following change types can be displayed:
              CHARACTER    CHANGE TYPE
              +            file was added
              -            file was removed
              M            file was modified
              R            file was renamed
        -F      Display a single letter for the file type in second to last
                column.
                The following file types can be displayed:
                      CHARACTER    FILE TYPE
                      F            file
                      /            directory
                      B            block device
                      @            symbolic link
                      =            socket
                      >            door (not supported on FreeBSD)
                      |            FIFO (not supported on FreeBSD)
                      P            event portal (not supported on FreeBSD)
        -H      Machine-parseable output, fields separated a tab character.
        -t      Display a change timestamp in the first column.
    zfs jail jailid filesystem
        Attaches the specified filesystem to the jail identified by JID
        jailid.  From now on this file system tree can be managed from within
        a jail if the jailed property has been set. To use this functional‐
        ity, the jail needs the enforce_statfs parameter set to 0 and the
        allow.mount parameter set to 1.
        See jail(8) for more information on managing jails and configuring
        the parameters above.
    zfs unjail jailid filesystem
        Detaches the specified filesystem from the jail identified by JID
        jailid.

[править] EXAMPLES

    Example 1 Creating a ZFS File System Hierarchy
      The following commands create a file system named pool/home and a file
      system named pool/home/bob.  The mount point /home is set for the par‐
      ent file system, and is automatically inherited by the child file sys‐
      tem.
        # zfs create pool/home
        # zfs set mountpoint=/home pool/home
        # zfs create pool/home/bob
    Example 2 Creating a ZFS Snapshot
      The following command creates a snapshot named yesterday.  This snap‐
      shot is mounted on demand in the .zfs/snapshot directory at the root of
      the pool/home/bob file system.
        # zfs snapshot pool/home/bob@yesterday
    Example 3 Creating and Destroying Multiple Snapshots
      The following command creates snapshots named yesterday of pool/home
      and all of its descendent file systems. Each snapshot is mounted on
      demand in the .zfs/snapshot directory at the root of its file system.
      The second command destroys the newly created snapshots.
        # zfs snapshot -r pool/home@yesterday
        # zfs destroy -r pool/home@yesterday
    Example 4 Disabling and Enabling File System Compression
      The following command disables the compression property for all file
      systems under pool/home.  The next command explicitly enables
      compression for pool/home/anne.
        # zfs set compression=off pool/home
        # zfs set compression=on pool/home/anne
    Example 5 Listing ZFS Datasets
      The following command lists all active file systems and volumes in the
      system.  Snapshots are displayed if the listsnaps property is on.  The
      default is off.  See zpool(8) for more information on pool properties.
        # zfs list
           NAME                      USED  AVAIL  REFER  MOUNTPOINT
           pool                      450K   457G    18K  /pool
           pool/home                 315K   457G    21K  /home
           pool/home/anne             18K   457G    18K  /home/anne
           pool/home/bob             276K   457G   276K  /home/bob
    Example 6 Setting a Quota on a ZFS File System
      The following command sets a quota of 50 Gbytes for pool/home/bob.
        # zfs set quota=50G pool/home/bob
    Example 7 Listing ZFS Properties
      The following command lists all properties for pool/home/bob.
        # zfs get all pool/home/bob
        NAME           PROPERTY              VALUE                  SOURCE
        pool/home/bob  type                  filesystem             -
        pool/home/bob  creation              Tue Jul 21 15:53 2009  -
        pool/home/bob  used                  21K                    -
        pool/home/bob  available             20.0G                  -
        pool/home/bob  referenced            21K                    -
        pool/home/bob  compressratio         1.00x                  -
        pool/home/bob  mounted               yes                    -
        pool/home/bob  quota                 20G                    local
        pool/home/bob  reservation           none                   default
        pool/home/bob  recordsize            128K                   default
        pool/home/bob  mountpoint            /home/bob              default
        pool/home/bob  sharenfs              off                    default
        pool/home/bob  checksum              on                     default
        pool/home/bob  compression           on                     local
        pool/home/bob  atime                 on                     default
        pool/home/bob  devices               on                     default
        pool/home/bob  exec                  on                     default
        pool/home/bob  setuid                on                     default
        pool/home/bob  readonly              off                    default
        pool/home/bob  jailed                off                    default
        pool/home/bob  snapdir               hidden                 default
        pool/home/bob  aclmode               discard                default
        pool/home/bob  aclinherit            restricted             default
        pool/home/bob  canmount              on                     default
        pool/home/bob  xattr                 on                     default
        pool/home/bob  copies                1                      default
        pool/home/bob  version               5                      -
        pool/home/bob  utf8only              off                    -
        pool/home/bob  normalization         none                   -
        pool/home/bob  casesensitivity       sensitive              -
        pool/home/bob  vscan                 off                    default
        pool/home/bob  nbmand                off                    default
        pool/home/bob  sharesmb              off                    default
        pool/home/bob  refquota              none                   default
        pool/home/bob  refreservation        none                   default
        pool/home/bob  primarycache          all                    default
        pool/home/bob  secondarycache        all                    default
        pool/home/bob  usedbysnapshots       0                      -
        pool/home/bob  usedbydataset         21K                    -
        pool/home/bob  usedbychildren        0                      -
        pool/home/bob  usedbyrefreservation  0                      -
        pool/home/bob  logbias               latency                default
        pool/home/bob  dedup                 off                    default
        pool/home/bob  mlslabel                                     -
        pool/home/bob  sync                  standard               default
        pool/home/bob  refcompressratio      1.00x                  -
      The following command gets a single property value.
        # zfs get -H -o value compression pool/home/bob
        on
      The following command lists all properties with local settings for
      pool/home/bob.
        # zfs get -s local -o name,property,value all pool/home/bob
        NAME           PROPERTY              VALUE
        pool/home/bob  quota                 20G
        pool/home/bob  compression           on
    Example 8 Rolling Back a ZFS File System
      The following command reverts the contents of pool/home/anne to the
      snapshot named yesterday, deleting all intermediate snapshots.
        # zfs rollback -r pool/home/anne@yesterday
    Example 9 Creating a ZFS Clone
      The following command creates a writable file system whose initial con‐
      tents are the same as pool/home/bob@yesterday.
        # zfs clone pool/home/bob@yesterday pool/clone
    Example 10 Promoting a ZFS Clone
      The following commands illustrate how to test out changes to a file
      system, and then replace the original file system with the changed one,
      using clones, clone promotion, and renaming:
        # zfs create pool/project/production
      Populate /pool/project/production with data and continue with the fol‐
      lowing commands:
        # zfs snapshot pool/project/production@today
        # zfs clone pool/project/production@today pool/project/beta
      Now make changes to /pool/project/beta and continue with the following
      commands:
        # zfs promote pool/project/beta
        # zfs rename pool/project/production pool/project/legacy
        # zfs rename pool/project/beta pool/project/production
      Once the legacy version is no longer needed, it can be destroyed.
        # zfs destroy pool/project/legacy
    Example 11 Inheriting ZFS Properties
      The following command causes pool/home/bob and pool/home/anne to
      inherit the checksum property from their parent.
        # zfs inherit checksum pool/home/bob pool/home/anne
    Example 12 Remotely Replicating ZFS Data
      The following commands send a full stream and then an incremental
      stream to a remote machine, restoring them into poolB/received/fs@a and
      poolB/received/fs@b, respectively.  poolB must contain the file system
      poolB/received, and must not initially contain poolB/received/fs.
        # zfs send pool/fs@a | ssh host zfs receive poolB/received/fs@a
        # zfs send -i a pool/fs@b | ssh host zfs receive poolB/received/fs
    Example 13 Using the "zfs receive -d" Option
      The following command sends a full stream of poolA/fsA/fsB@snap to a
      remote machine, receiving it into poolB/received/fsA/fsB@snap.  The
      fsA/fsB@snap portion of the received snapshot's name is determined from
      the name of the sent snapshot.  poolB must contain the file system
      poolB/received.  If poolB/received/fsA does not exist, it is created as
      an empty file system.
        # zfs send poolA/fsA/fsB@snap | ssh host zfs receive -d poolB/received
    Example 14 Setting User Properties
      The following example sets the user-defined com.example:department
      property for a dataset.
        # zfs set com.example:department=12345 tank/accounting
    Example 15 Performing a Rolling Snapshot
      The following example shows how to maintain a history of snapshots with
      a consistent naming scheme. To keep a week's worth of snapshots, the
      user destroys the oldest snapshot, renames the remaining snapshots, and
      then creates a new snapshot, as follows:
        # zfs destroy -r pool/users@7daysago
        # zfs rename -r pool/users@6daysago @7daysago
        # zfs rename -r pool/users@5daysago @6daysago
        # zfs rename -r pool/users@yesterday @5daysago
        # zfs rename -r pool/users@yesterday @4daysago
        # zfs rename -r pool/users@yesterday @3daysago
        # zfs rename -r pool/users@yesterday @2daysago
        # zfs rename -r pool/users@today @yesterday
        # zfs snapshot -r pool/users@today
    Example 16 Setting "sharenfs" Property Options on a ZFS File System
      The following command shows how to set sharenfs property options to
      enable root access for a specific network on the tank/home file system.
      The contents of the sharenfs property are valid exports(5) options.
        # zfs set sharenfs="maproot=root,network 192.168.0.0/24" tank/home
      Another way to write this command with the same result is:
        # set zfs sharenfs="-maproot=root -network 192.168.0.0/24" tank/home
    Example 17 Delegating ZFS Administration Permissions on a ZFS Dataset
      The following example shows how to set permissions so that user cindys
      can create, destroy, mount, and take snapshots on tank/cindys.  The
      permissions on tank/cindys are also displayed.
        # zfs allow cindys create,destroy,mount,snapshot tank/cindys
        # zfs allow tank/cindys
        -------------------------------------------------------------
        Local+Descendent permissions on (tank/cindys)
                  user cindys create,destroy,mount,snapshot
        -------------------------------------------------------------
    Example 18 Delegating Create Time Permissions on a ZFS Dataset
      The following example shows how to grant anyone in the group staff to
      create file systems in tank/users.  This syntax also allows staff mem‐
      bers to destroy their own file systems, but not destroy anyone else's
      file system. The permissions on tank/users are also displayed.
        # zfs allow staff create,mount tank/users
        # zfs allow -c destroy tank/users
        # zfs allow tank/users
        -------------------------------------------------------------
        Create time permissions on (tank/users)
                  create,destroy
        Local+Descendent permissions on (tank/users)
                  group staff create,mount
        -------------------------------------------------------------
    Example 19 Defining and Granting a Permission Set on a ZFS Dataset
      The following example shows how to define and grant a permission set on
      the tank/users file system. The permissions on tank/users are also dis‐
      played.
        # zfs allow -s @pset create,destroy,snapshot,mount tank/users
        # zfs allow staff @pset tank/users
        # zfs allow tank/users
        -------------------------------------------------------------
        Permission sets on (tank/users)
                @pset create,destroy,mount,snapshot
        Create time permissions on (tank/users)
                create,destroy
        Local+Descendent permissions on (tank/users)
                group staff @pset,create,mount
        -------------------------------------------------------------
    Example 20 Delegating Property Permissions on a ZFS Dataset
      The following example shows to grant the ability to set quotas and
      reservations on the users/home file system. The permissions on
      users/home are also displayed.
        # zfs allow cindys quota,reservation users/home
        # zfs allow cindys
        -------------------------------------------------------------
        Local+Descendent permissions on (users/home)
                user cindys quota,reservation
        -------------------------------------------------------------
        # su - cindys
        cindys% zfs set quota=10G users/home/marks
        cindys% zfs get quota users/home/marks
        NAME              PROPERTY  VALUE             SOURCE
        users/home/marks  quota     10G               local
    Example 21 Removing ZFS Delegated Permissions on a ZFS Dataset
      The following example shows how to remove the snapshot permission from
      the staff group on the tank/users file system. The permissions on
      tank/users are also displayed.
        # zfs unallow staff snapshot tank/users
        # zfs allow tank/users
        -------------------------------------------------------------
        Permission sets on (tank/users)
                @pset create,destroy,mount,snapshot
        Create time permissions on (tank/users)
                create,destroy
        Local+Descendent permissions on (tank/users)
                group staff @pset,create,mount
        -------------------------------------------------------------

[править] EXIT STATUS

    The following exit values are returned:
      0   Successful completion.
      1   An error occurred.
      2   Invalid command line options were specified.

[править] SEE ALSO

    chmod(2), fsync(2), exports(5), fstab(5), rc.conf(5), jail(8), mount(8),
    umount(8), zpool(8)

[править] AUTHORS

    This manual page is a mdoc(7) reimplementation of the OpenSolaris manual
    page zfs(1M), modified and customized for FreeBSD and licensed under the
    Common Development and Distribution License (CDDL).
    The mdoc(7) implementation of this manual page was initially written by
    Martin Matuska <mm@FreeBSD.org>.

FreeBSD 9.0 November 26, 2011 FreeBSD 9.0

Источник — «http://xgu.ru/wiki/man/orig/zfs»