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zfs(1M)                 System Administration Commands                 zfs(1M)



NAME
       zfs - configures ZFS file systems

SYNOPSIS
       zfs [-?]


       zfs create [[-o property=value]]... filesystem


       zfs create [-s] [-b blocksize] [[-o property=value]]... -V size volume


       zfs destroy [-rRf] filesystem|volume|snapshot


       zfs clone snapshot filesystem|volume


       zfs promote filesystem


       zfs rename filesystem|volume|snapshot
           [filesystem|volume|snapshot]


       zfs snapshot [-r] filesystem@name|volume@name


       zfs rollback [-rRf] snapshot


       zfs list [-rH] [-o prop[,prop] ]... [ -t type[,type]...]
           [ -s prop [-s prop]... [ -S prop [-S prop]...
           [filesystem|volume|snapshot|/pathname|./pathname ...


       zfs set property=value filesystem|volume ...


       zfs get [-rHp] [-o field[,field]...]
           [-s source[,source]...] all | property[,property]...
            filesystem|volume|snapshot ...


       zfs inherit [-r] property filesystem|volume... ...


       zfs mount


       zfs mount [-o options] [-O] -a


       zfs mount [-o options] [-O] filesystem


       zfs unmount [-f] -a


       zfs unmount [-f] filesystem|mountpoint


       zfs share -a


       zfs share filesystem


       zfs unshare [-f] -a


       zfs unshare [-f] filesystem|mountpoint


       zfs send [-i snapshot1] snapshot2


       zfs receive [-vnF ] filesystem|volume|snapshot


       zfs receive [-vnF ] -d filesystem

       zfs jail jailid filesystem

       zfs unjail jailid filesystem


DESCRIPTION
       The zfs command configures ZFS datasets within a ZFS storage pool, as
       described in zpool(1M). 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 standard POSIX file system. ZFS file systems can be
                      mounted within the standard file system namespace and
                      behave like any other file system.


       volume
                      A logical volume exported as a raw or block device. This
                      type of dataset should only be used under special
                      circumstances. File systems are typically used in most
                      environments. Volumes cannot be used in a non-global
                      zone.


       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(1M) command.

       See zpool(1M) 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 original 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 will likely be numerous. To cope with this, ZFS
       automatically manages mounting and unmounting file systems without the
       need to edit the /etc/vfstab 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/vfstab). The mountpoint property can be
       inherited, so if pool/home has a mount point of /export/stuff, then
       pool/home/user automatically inherits a mount point of
       /export/stuff/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, umount, /etc/vfstab). If a file system's mount point is set to
       "legacy", ZFS makes no attempt to manage the file system, and the
       administrator is responsible for mounting and unmounting the file
       system.

   Zones
       A ZFS file system can be added to a non-global zone by using zonecfg's
       "add fs" subcommand. A ZFS file system that is added to a non-global
       zone must have its mountpoint property set to legacy.

       The physical properties of an added file system are controlled by the
       global administrator. However, the zone administrator can create,
       modify, or destroy files within the added file system, depending on how
       the file system is mounted.

       A dataset can also be delegated to a non-global zone by using zonecfg's
       "add dataset" subcommand. You cannot delegate a dataset to one zone and
       the children of the same dataset to another zone. The zone
       administrator can change properties of the dataset or any of its
       children. However, the "quota" property is controlled by the global
       administrator.

       A ZFS volume can be added as a device to a non-global zone by using
       zonecfg's "add device" subcommand. However, its physical properties can
       only be modified by the global administrator.

       For more information about zonecfg syntax, see zonecfg(1M).

       After a dataset is delegated to a non-global zone, the "zoned" property
       is automatically set. A zoned file system cannot be mounted in the
       global zone, since the zone administrator might have to set the mount
       point to an unacceptable value.

       The global administrator can forcibly clear the "zoned" property,
       though this should be done with extreme care. The global administrator
       should verify that all the mount points are acceptable before clearing
       the property.

   Native Properties
       Properties are divided into two types, native properties and user
       defined properties. Native properties either export internal statistics
       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.

       Every dataset has a set of properties that export statistics about the
       dataset as well as control various behavior. Properties are inherited
       from the parent unless overridden by the child. Snapshot properties can
       not be edited; they always inherit their inheritable properties.
       Properties that are not applicable to snapshots are not displayed.

       The values of numeric properties can be specified using the following
       human-readable suffixes (for example, "k", "KB", "M", "Gb", etc, 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
       lowercase, except for "mountpoint" and "sharenfs".

       The first set of properties consist of read-only statistics about the
       dataset. These properties cannot be set, nor are they inherited. Native
       properties apply to all dataset types unless otherwise noted.

       type
                        The type of dataset: "filesystem", "volume",
                        "snapshot", or "clone".


       creation
                        The time this dataset was created.


       used
                        The amount of space consumed by this dataset and all
                        its descendants. This is the value that is checked
                        against this dataset's quota and reservation. The
                        space used does not include this dataset's
                        reservation, but does take into account the
                        reservations of any descendant datasets.  The amount
                        of space that a dataset consumes from its parent, as
                        well as the amount of space that will be 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 snapshots 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(3c)
                        or O_SYNC does not necessarily guarantee that the
                        space usage information is updated immediately.


       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".


       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".


       compressratio
                        The compression ratio achieved for this dataset,
                        expressed as a multiplier. Compression can be turned
                        on by running "zfs set compression=on dataset". The
                        default value 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. The origin cannot be
                        destroyed (even with the -r or -f options) so long as
                        a clone exists.


       The following two properties can be set to control the way space is
       allocated between datasets. These properties are not inherited, but do
       affect their descendants.

       quota=size | none
           Limits the amount of space a dataset and its descendants can
           consume. This property enforces a hard limit on the amount of space
           used. This includes all space consumed by descendants, including
           file systems and snapshots. Setting a quota on a descendant 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.


       reservation=size | none
           The minimum amount of space guaranteed to a dataset and its
           descendants. 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".


       volsize=size
           For volumes, specifies the logical size of the volume. By default,
           creating a volume establishes a reservation of equal size. Any
           changes to volsize are reflected in an equivalent change to the
           reservation. 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 volume 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 (particularly when shrinking the size). Extreme care should
           be used when adjusting the volume size.

           Though not recommended, a "sparse volume" (also known as "thin
           provisioning") 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 volume can fail with ENOSPC when the pool is low on space.
           For a sparse volume, changes to volsize are not reflected in the
           reservation.


       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".


       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 only affects files created
           afterward; existing files are unaffected.

           This property can also be referred to by its shortened column name,
           "recsize".


       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.


       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 through traditional tools such as share(1M),
           unshare(1M), and dfstab(4). Otherwise, the file system is
           automatically shared and unshared with the "zfs share" and "zfs
           unshare" commands. If the property is set to "on", the share(1M)
           command is invoked with no options. Otherwise, the share(1M)
           command is invoked with options equivalent to the contents of this
           property.

           When the "sharenfs" property is changed for a dataset, the dataset
           and any children inheriting the property are re-shared with the new
           options, only if the property was previously "off", or if they were
           shared before the property was changed. If the new property is
           "off", the file systems are unshared.


       shareiscsi=on | off
           Like the "sharenfs" property, "shareiscsi" indicates whether a ZFS
           volume is exported as an iSCSI target. The acceptable values for
           this property are "on", "off", and "type=disk".  The default value
           is "off". In the future, other target types might be supported. For
           example, "tape".

           You might want to set "shareiscsi=on" for a file system so that all
           ZFS volumes within the file system are shared by default. Setting
           this property on a file system has no direct effect, however.


       checksum=on | off | fletcher2, | fletcher4 | sha256
           Controls the checksum used to verify data integrity. The default
           value is "on", which automatically selects an appropriate algorithm
           (currently, fletcher2, but this may change in future releases). The
           value "off" disables integrity checking on user data. Disabling
           checksums is NOT a recommended practice.


       compression=on | off | lzjb | gzip | gzip-N
           Controls the compression algorithm used for this dataset. The
           "lzjb" compression algorithm is optimized for performance while
           providing decent data compression. Setting compression to "on" uses
           the "lzjb" compression algorithm. The "gzip" compression algorithm
           uses the same compression 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)).

           This property can also be referred to by its shortened column name
           "compress".


       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".


       devices=on | off
           Controls whether device nodes can be opened on this file system.
           The default value is "on".


       exec=on | off
           Controls whether processes can be executed from within this file
           system. The default value is "on".


       setuid=on | off
           Controls whether the set-UID bit is respected for the file system.
           The default value is "on".


       readonly=on | off
           Controls whether this dataset can be modified. The default value is
           "off".

           This property can also be referred to by its shortened column name,
           "rdonly".


       zoned=on | off
           Controls whether the dataset is managed from a non-global zone. See
           the "Zones" section for more information. The default value is
           "off".


       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".


       aclmode=discard | groupmask | passthrough
           Controls how an ACL is modified during chmod(2). A file system with
           an "aclmode" property of "discard" deletes all ACL entries that do
           not represent the mode of the file. An "aclmode" property of
           "groupmask" (the default) reduces user or group permissions. The
           permissions are reduced, such that they are no greater than the
           group permission bits, unless it is a user entry that has the same
           UID as the owner of the file or directory. In this case, the ACL
           permissions are reduced so that they are no greater than owner
           permission bits. A file system with an "aclmode" property of
           "passthrough" indicates that no changes will be made to the ACL
           other than generating the necessary ACL entries to represent the
           new mode of the file or directory.


       aclinherit=discard | noallow | secure | passthrough
           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" property value of "noallow" only inherits inheritable
           ACL entries that specify "deny" permissions. The property value
           "secure" (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.


       canmount=on | off
           If this property is set to "off", the file system cannot be
           mounted, and is ignored by "zfs mount -a". This is similar to
           setting the "mountpoint" property to "none", except that the
           dataset still has a normal "mountpoint" property which can be
           inherited. This allows datasets to be used solely as a mechanism to
           inherit properties. One use case is to have two logically separate
           datasets have the same mountpoint, so that the children of both
           datasets appear in the same directory, but may have different
           inherited characteristics. The default value is "on".

           This property is not inherited.


       xattr=on | off
           Controls whether extended attributes are enabled for this file
           system. The default value is "on".


       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=" option.


       jailed=on | off
           Controls whether the dataset is managed from within a jail. The
           default value is "off".


   iscsioptions
       This read-only property, which is hidden, is used by the iSCSI target
       daemon to store persistent information, such as the IQN. It cannot be
       viewed or modified using the zfs command. The contents are not intended
       for external consumers.

   Temporary Mount Point Properties
       When a file system is mounted, either through mount(1M) 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
             devices                 devices/nodevices
             exec                    exec/noexec
             readonly                ro/rw
             setuid                  setuid/nosetuid
             xattr                   xattr/noxattr



       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. The -nosuid option is an alias for "nodevices,nosetuid".
       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.

       User property names must contain a colon (":") character, to
       distinguish them from native properties. They might 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
       inherited, and are never validated. All of the commands that operate on
       properties ("zfs list", "zfs get", "zfs set", etc.) 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 limited to 1024 characters.

   Volumes as Swap or Dump Devices
       To set up a swap area, create a ZFS volume of a specific size and then
       enable swap on that device. For more information, see the EXAMPLES
       section.

       Do not swap to a file on a ZFS file system. A ZFS swap file
       configuration is not supported.

       Using a ZFS volume as a dump device is not supported.

SUBCOMMANDS
       All subcommands that modify state are logged persistently to the pool
       in their original form.

       zfs ?
           Displays a help message.


       zfs create [[-o property=value]...] filesystem
           Creates a new ZFS file system. The file system is automatically
           mounted according to the "mountpoint" property inherited from the
           parent.

           -o property=value
                                Sets the specified property as if "zfs set
                                property=value" 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
                                multiple -o options.



       zfs create [-s] [-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/{dsk,rdsk}/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.

           -s
                                Creates a sparse volume with no reservation.
                                See "volsize" in the Native Properties section
                                for more information about sparse volumes.


           -o property=value
                                Sets the specified property as if "zfs set
                                property=value" 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
                                multiple -o options.


           -b blocksize
                                Equivalent to "-o volblocksize=blocksize". If
                                this option is specified in conjunction with
                                "-o volblocksize", the resulting behavior is
                                undefined.



       zfs destroy [-rRf] filesystem|volume|snapshot
           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, snapshots, clones).

           -r
                 Recursively destroy all children. If a snapshot is specified,
                 destroy all snapshots with this name in descendant file
                 systems.


           -R
                 Recursively destroy all dependents, including cloned file
                 systems outside the target hierarchy. If a snapshot is
                 specified, destroy all snapshots with this name in descendant
                 file systems.


           -f
                 Force an unmount of any file systems using the "unmount -f"
                 command. This option has no effect on non-file systems or
                 unmounted file systems.

           Extreme care should be taken when applying either the -r or the -f
           options, as they can destroy large portions of a pool and cause
           unexpected behavior for mounted file systems in use.


       zfs clone 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
           hierarchy, and is created as the same type as the original.


       zfs promote filesystem
           Promotes a clone file system to no longer be dependent on its
           "origin" snapshot. This makes it possible to destroy the file
           system that the clone was created from. The clone parent-child
           dependency relationship is reversed, so that the "origin" file
           system becomes a clone of the specified file system.

           The snaphot 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
           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
           renaming 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.


       zfs snapshot [-r] filesystem@name|volume@name
           Creates a snapshot with the given name. See the "Snapshots" section
           for details.

           -r
                 Recursively create snapshots of all descendant datasets.
                 Snapshots are taken atomically, so that all recursive
                 snapshots correspond to the same moment in time.



       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
           discarded, and the dataset reverts to the state at the time of the
           snapshot. 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. The file system is unmounted and remounted, if necessary.

           -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
                 Force an unmount of any file systems using the "unmount -f"
                 command.



       zfs list [-rH] [-o prop[,prop] ]... [ -t type[,type]...] [ -s prop [-s
       prop]... [ -S prop [-S prop]...
       [filesystem|volume|snapshot|/pathname|./pathname ...
           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
           datasets are displayed and contain the following fields:

             name,used,available,referenced,mountpoint



           -H
                      Used for scripting mode. Do not print headers and
                      separate fields by a single tab instead of arbitrary
                      whitespace.


           -r
                      Recursively display any children of the dataset on the
                      command line.


           -o prop
                      A comma-separated list of properties to display. The
                      property must be one of the properties described in the
                      "Native Properties" section, or the special value "name"
                      to display the dataset name.


           -s prop
                      A property to use 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" section, or the special value "name" to
                      sort by the dataset name. Multiple properties can be
                      specified at one time using multiple -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:

                          o      Numeric types sort in numeric order.

                          o      String types sort in alphabetical order.

                          o      Types inappropriate for a row sort that row
                                 to the literal bottom, regardless of the
                                 specified ordering.

                          o      If no sorting options are specified the
                                 existing behavior of "zfs list" is preserved.


           -S prop
                      Same as the -s option, but sorts by property in
                      descending order.


           -t type
                      A comma-separated list of types to display, where "type"
                      is one of "filesystem", "snapshot" or "volume". For
                      example, specifying "-t snapshot" displays only
                      snapshots.



       zfs set property=value filesystem|volume ...
           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-
           readable form with a suffix of "B", "K", "M", "G", "T", "P", "E",
           "Z" (for bytes, Kbytes, Mbytes, gigabytes, terabytes, petabytes,
           exabytes, or zettabytes, respectively). Properties cannot be set on
           snapshots.


       zfs get [-rHp] [-o field[,field]...] [-s source[,source]...] all |
       property[,property]... filesystem|volume|snapshot ...
           Displays properties for the given datasets. If no datasets are
           specified, 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,
                           temporary, inherited, or none (-).


           All columns are displayed by default, though this can be controlled
           by using the -o option. This command 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 for
           the given dataset.

           -r
                        Recursively display properties for any 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.


           -o field
                        A comma-separated list of columns to display.
                        "name,property,value,source" is the default value.


           -s source
                        A comma-separated list of sources to display. Those
                        properties coming from a source other than those in
                        this list are ignored. Each source must be one of the
                        following: "local,default,inherited,temporary,none".
                        The default value is all sources.


           -p
                        Display numbers in parsable (exact) values.



       zfs inherit [-r] property filesystem|volume ...
           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 values, and details on which properties can be inherited.

           -r
                 Recursively inherit the given property for all children.



       zfs mount
           Displays all ZFS file systems currently mounted.


       zfs mount[-o opts] [-O] -a
           Mounts all available ZFS file systems. Invoked automatically as
           part of the boot process.

           -o opts
                      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.


           -O
                      Perform an overlay mount. See mount(1M) for more
                      information.



       zfs mount [-o opts] [-O] filesystem
           Mounts a specific ZFS file system. This is typically not necessary,
           as file systems are automatically mounted when they are created or
           the mountpoint property has changed. See the "Mount Points" section
           for details.

           -o opts
                      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.


           -O
                      Perform an overlay mount. See mount(1M) for more
                      information.



       zfs unmount -a
           Unmounts all currently mounted ZFS file systems. Invoked
           automatically as part of the shutdown process.


       zfs unmount [-f] filesystem|mountpoint
           Unmounts the given file system. The command can also be given a
           path to a ZFS file system mount point on the system.

           -f
                 Forcefully unmount the file system, even if it is currently
                 in use.



       zfs share -a
           Shares all available ZFS file systems. This is invoked
           automatically as part of the boot process.


       zfs share filesystem
           Shares a specific ZFS file system according to the "sharenfs"
           property. File systems are shared when the "sharenfs" property is
           set.


       zfs unshare -a
           Unshares all currently shared ZFS file systems. This is invoked
           automatically as part of the shutdown process.


       zfs unshare [-F] filesystem|mountpoint
           Unshares the given file system. The command can also be given a
           path to a ZFS file system shared on the system.

           -F
                 Forcefully unshare the file system, even if it is currently
                 in use.



       zfs send [-i snapshot1] snapshot2
           Creates a stream representation of snapshot2, 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 snapshot1
                           Generate an incremental stream from snapshot1 to
                           snapshot2. The incremental source snapshot1 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
                           snapshot2.



       The format of the stream is evolving. No backwards compatibility is
       guaranteed. You may not be able to receive your streams on future
       versions of ZFS.

       zfs receive [-vnF] filesystem|volume|snapshot
       zfs receive [-vnF] -d filesystem
           Creates a snapshot whose contents are as specified in the stream
           provided 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
           system must already exist, and its most recent snapshot must match
           the incremental stream's source. The destination file system and
           all of its child file systems are unmounted and cannot be accessed
           during the receive operation.

           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 option.

           If the argument is a snapshot name, the specified snapshot is
           created. If the argument is a file system or volume name, a
           snapshot with the same name as the sent snapshot is created within
           the specified filesystem or volume.  If the -d 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,
           any required file systems within the specified one are created.

           -d
                 Use the name of the sent snapshot to determine the name of
                 the new snapshot as described in the paragraph above.


           -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 determine what name the
                 receive operation would use.


           -F
                 Force a rollback of the filesystem to the most recent
                 snapshot before performing the receive operation.



       zfs jail jailid filesystem
           Attaches the given file system to the given jail. From now on this
           file system tree can be managed from within a jail if the "jailed"
           property has been set.  To use this functionality, sysctl
           security.jail.enforce_statfs should be set to 0 and sysctl
           security.jail.mount_allowed should be set to 1.


       zfs unjail jailid filesystem
           Detaches the given file system from the given jail.


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 "/export/home" is
       set for the parent file system, and automatically inherited by the
       child file system.


         # zfs create pool/home
         # zfs set mountpoint=/export/home pool/home
         # zfs create pool/home/bob



       Example 2 Creating a ZFS Snapshot

       The following command creates a snapshot named "yesterday". This
       snapshot 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 Taking and destroying multiple snapshots

       The following command creates snapshots named "yesterday" of
       "pool/home" and all of its descendant 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 Turning Off Compression

       The following commands turn compression off for all file systems under
       "pool/home", but explicitly turns it on 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.


         # zfs list


           NAME                      USED  AVAIL  REFER  MOUNTPOINT
           pool                      100G   60G       -  /pool
           pool/home                 100G   60G       -  /export/home
           pool/home/bob              40G   60G     40G  /export/home/bob
           pool/home/bob@yesterday     3M     -     40G  -
           pool/home/anne             60G   60G     40G  /export/home/anne



       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       Fri Feb 23 14:20 2007  -
           pool/home/bob  used           24.5K                  -
           pool/home/bob  available      50.0G                  -
           pool/home/bob  referenced     24.5K                  -
           pool/home/bob  compressratio  1.00x                  -
           pool/home/bob  mounted        yes                    -
           pool/home/bob  quota          50G                    local
           pool/home/bob  reservation    none                   default
           pool/home/bob  recordsize     128K                   default
           pool/home/bob  mountpoint     /pool/home/bob         default
           pool/home/bob  sharenfs       off                    default
           pool/home/bob  shareiscsi     off                    default
           pool/home/bob  checksum       on                     default
           pool/home/bob  compression    off                    default
           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  zoned          off                    default
           pool/home/bob  snapdir        hidden                 default
           pool/home/bob  aclmode        groupmask              default
           pool/home/bob  aclinherit     secure                 default
           pool/home/bob  canmount       on                     default
           pool/home/bob  xattr          on                     default





       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 -r -s local -o name,property,value all pool/home/bob

           NAME             PROPERTY      VALUE
           pool             compression   on
           pool/home        checksum      off



       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
       contents 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
         # zfs snapshot pool/project/production@today
         # zfs clone pool/project/production@today pool/project/beta
          make changes to /pool/project/beta and test them
         # 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
       will be created as an empty file system.


         # zfs send poolA/fsA/fsB@snap | \
           ssh host zfs receive -d poolB/received




       Example 14 Creating a ZFS volume as a Swap Device

       The following example shows how to create a 5-Gbyte ZFS volume and then
       add the volume as a swap device.


         # zfs create  -V 5gb tank/vol
         # swap -a /dev/zvol/dsk/tank/vol



       Example 15 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 16 Creating a ZFS Volume as a iSCSI Target Device

       The following example shows how to create a ZFS volume as an iSCSI
       target.


         # zfs create -V 2g pool/volumes/vol1
         # zfs set shareiscsi=on pool/volumes/vol1
         # iscsitadm list target
         Target: pool/volumes/vol1
         iSCSI Name:
         iqn.1986-03.com.sun:02:7b4b02a6-3277-eb1b-e686-a24762c52a8c
         Connections: 0



       After the iSCSI target is created, set up the iSCSI initiator. For more
       information about the Solaris iSCSI initiator, see the Solaris
       Administration Guide: Devices and File Systems.

EXIT STATUS
       The following exit values are returned:

       0
            Successful completion.


       1
            An error occurred.


       2
            Invalid command line options were specified.


ATTRIBUTES
       See attributes(5) for descriptions of the following attributes:





SEE ALSO
       gzip(1), ssh(1), mount(1M), share(1M), unshare(1M), zonecfg(1M),
       zpool(1M), chmod(2), stat(2), fsync(3c), dfstab(4), attributes(5)



SunOS 5.11                        16 Mar 2007                          zfs(1M)