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

NAME
zfs - configures ZFS file systems

SYNOPSIS
zfs [-?]

zfs help subcommand | help property property |permission

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

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

zfs destroy [-rRf] filesystem|volume

zfs destroy [-rRd] snapshot

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 list [-r|-d depth][-H][-o property[,...]] [-t type[,...]]
[-s property] ... [-S property] ... [filesystem|volume|snapshot] ...

zfs set [-r] property=value filesystem|volume|snapshot ...

zfs inherit [-rS] property filesystem|volume|snapshot ...

zfs upgrade

zfs upgrade [-v]

zfs upgrade [-r] [-V version] -a | filesystem

zfs userspace [-niHp] [-o field[,...]] [-sS field] ...
[-t type [,...]] filesystem|snapshot

zfs groupspace [-hniHp] [-o field[,...]] [-sS field] ...
[-t type [,...]] filesystem|snapshot

zfs mount

zfs mount [-vO] [-o options] -a | filesystem

zfs unmount [-f] -a | filesystem|mountpoint

zfs share -a | filesystem

zfs unshare -a filesystem|mountpoint

zfs send [-Rbpv] [-[iI] snapshot] snapshot

zfs send -r [-bcpv] [-[i] snapshot] snapshot

zfs receive [-vnFu] [[-o property=value] | [-x property]] ...
filesystem|volume|snapshot

zfs receive [-vnFu] [[-o property=value] | [-x property]] ...
[-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 [-FHte] [-o field] ... snapshot snapshot|filesystem
zfs diff -E [-FHt] [-o field] ... snapshot|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 ZFS dataset of type filesystem can be mounted within the standard
system namespace and behaves like other file systems. While ZFS
file systems are designed to be POSIX compliant, 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 circumstances. File sys‐
tems are typically used in most environments.

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 is likely to 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 sys‐
tems 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 prop‐
erty. This directory is created as needed, and ZFS automatically mounts
the file system when the zfs mount -a command is invoked (without edit‐
ing /etc/vfstab). The mountpoint property can be inherited, so if
pool/home has a mount point of /export/stuff, then pool/home/user auto‐
matically inherits a mount point of /export/stuff/user.

A file system can be mounted temporarily at a location other than the
file systems's persistent mount point by specifying the -o mount‐
point=value option to the zfs mount command. This is only permitted for
file systems with non-legacy mount points.

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 admin‐
istrator is responsible for mounting and unmounting the file system.

Zones
A ZFS file system can be added to a non-global zone by using the
zonecfg 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, mod‐
ify, 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 the
zonecfg 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 chil‐
dren. However, the quota property is controlled by the global adminis‐
trator.

A ZFS volume can be added as a device to a non-global zone by using the
zonecfg add device subcommand. However, its physical properties can be
modified only 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 can only be mounted in the
global zone by use of a temporary mountpoint property (see "Temporary
Mount Point Properties").

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 (or "user") properties. Native properties either export inter‐
nal 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 proper‐
ties, 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 snap‐
shots).

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
lowercase, 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
properties 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

The compression ratio achieved for this dataset, expressed as a
multiplier. Compression can be turned on by running: zfs set com‐
pression=on dataset. The default value is off.

creation

The time this dataset was created.

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.

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 privi‐
lege with zfs allow, can access all groups' usage.

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.

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.

type

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

used

The amount of space consumed by this dataset and all its descen‐
dents. 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 refreservation
(through usedbyrefreservation) and the reservations of any descen‐
dent datasets (through usedbychildren). The amount of space that a
dataset consumes from its parent, 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
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.

usedby*

The usedby* properties decompose the used properties into the vari‐
ous reasons that space is used. Specifically, used = usedbychildren
+ usedbydataset + usedbyrefreservation +, usedbysnapshots. These
properties are only available for datasets created on zpool version
13 pools.

usedbychildren

The amount of space used by children of this dataset, which would
be freed if all the dataset's children were destroyed.

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).

usedbyrefreservation

The amount of space used by a refreservation set on this dataset,
which would be freed if the refreservation was removed.

Space accounted for by this property represents potential consump‐
tion by future writes, reserved in advance to prevent write alloca‐
tion failures in this dataset. This can include unwritten data,
space currently shared with snapshots, and compression savings for
volumes (which may be lost when replaced with less compressible
data). When allocations for later writes increase usedbydataset or
usedbysnapshots, usedbyrefreservation will decrease accordingly.

usedbysnapshots

The amount of space consumed by snapshots of this dataset. In par‐
ticular, it is the amount of space that would be freed if all of
this dataset's snapshots were destroyed. Note that this is not sim‐
ply the sum of the snapshots' used properties because space can be
shared by multiple snapshots.

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:

o POSIX name (for example, joe)

o POSIX numeric ID (for example, 789)

o SID name (for example, joe.smith@mydomain)

o SID numeric ID (for example, S-1-123-456-789)

userrefs

This property is set to the number of user holds on this snapshot.
User holds are set by using the zfs hold command.

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
KBs. Any power of 2 from 512 bytes to 1 MB is valid.

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

The following native properties can be used to change the behavior of a
ZFS dataset.

aclmode=discard | mask | 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 mask reduces user or group permissions. The permissions
are reduced so 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. The
mask value also preserves the ACL across mode changes (without an
explict ACL set [by means of chmod(1)] between the mode changes). A
file system with an aclmode property of passthrough indicates that
no changes will be made to the ACL other than generating the neces‐
sary ACL entries to represent the new mode of the file or direc‐
tory.

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
property 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 all ACEs inherit
the execute permission only if the file creation 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.

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 option 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 unmount -a command.

This property is not inherited.

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, fletcher4, but this may change in future releases). The
value off disables integrity checking on user data. Disabling
checksums is NOT a recommended practice.

Changing this property affects only newly-written data.

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. 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 prop‐
erty 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.

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.

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 privi‐
lege with zfs allow, can get and set all groups' quotas.

logbias = latency | throughput

Provides a hint to ZFS about handling of synchronous requests in
this dataset. If logbias is set to latency (the default), ZFS uses
the pool's log devices (if configured) to handle the requests at
low latency. If logbias is set to throughput, ZFS does not use the
configured pool log devices. Instead, ZFS optimizes synchronous
operations for global pool throughput and efficient use of
resources.

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 prop‐
erty 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

Controls whether the file system should be mounted with nbmand (Non
Blocking mandatory locks). This is used for SMB clients. Changes to
this property only take effect when the file system is umounted and
remounted. See mount(1M) for more information on nbmand mounts.

primarycache=all | none | metadata

Controls what is cached in the primary cache (ARC). 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.

quota=size | none

Limits the amount of space a dataset and its descendents can con‐
sume. 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.

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.

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 default recordsize is 128 KB. The size specified must be a
power of two greater than or equal to 512 and less than or equal to
1 MB.

Changing the file system's recordsize affects only files created
afterward; existing files and received data 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 usedbydataset space is below this value,
the dataset is treated as if it were taking up the amount of space
specified by refreservation. The usedbyrefreservation figure repre‐
sents this extra space, adding to the total used space charged to
the dataset, and in turn consuming from the parent datasets' usage,
quotas, and reservations. This protects the dataset from overcom‐
mitment of pool resources, by ensuring that space for future writes
is reserved in advance.

Space shared with snapshots can later be replaced with new data,
and the snapshot represents a committment to keep both copies. If
refreservation is set, usedbyrefreservation must be increased to
the full size of refreservation when taking a new snapshot,
accounting for this commitment. If there is insufficient space
available to the dataset for this increase, snapshot creation will
be denied.

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.

rstchown=on | off

Indicates whether the file system restricts users from giving away
their files by means of chown(1) or the chown(2) system call. The
default is to restrict chown. When rstchown is off then chown will
act as if the user has the PRIV_FILE_CHOWN_SELF privilege.

secondarycache=all | none | metadata

Controls what is cached in the secondary cache (L2ARC). 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 meta‐
data 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

Controls whether the file system is shared by using the Solaris SMB
service, and what options are to be used. A file system with the
sharesmb property set to off is managed through traditional tools
such as share_nfs(1M). Otherwise, the file system is automatically
shared and unshared with the zfs share and zfs unshare commands.

Because SMB shares requires a resource name, a unique resource name
is constructed from the dataset name. The constructed name is a
copy of the dataset name except that the characters in the dataset
name, which would be illegal in the resource name, are replaced
with underscore (_) characters. A pseudo property "name" is also
supported that allows you to replace the data set name with a spec‐
ified name. The specified name is then used to replace the prefix
dataset in the case of inheritance. For example, if the dataset
data/home/john is set to name=john, then data/home/john has a
resource name of john. If a child dataset of data/home/john/back‐
ups, it has a resource name of john_backups.

When SMB shares are created, the SMB share name appears as an entry
in the .zfs/shares directory. You can use the ls or chmod command
to display the share-level ACLs on the entries in this directory.

When the sharesmb 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 set to off, or if they
were shared before the property was changed. If the new property is
set to off, the file systems are unshared.

Note -

This SMB-related property is not fully functional in the Oracle
Solaris 10 release because the Oracle Solaris SMB server is not
supported in the Oracle Solaris 10 release.

sharenfs=on | off | opts

Controls whether the dataset is shared by using the NFS protocol.
If the property is set to on, the zfs share command is invoked with
no options. You can specify a comma-separated list of options as
the contents of this property. See the EXAMPLES section. You can
also share a ZFS file system by using the zfs share command. Set‐
ting the sharenfs property or using the zfs share command is pre‐
ferred over using the legacy share(1M) command.

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.

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

Determines the degree to which file system transactions are syn‐
chronized. This property can be set when a dataset is created, or
dynamically, and will take effect immediately. sync can have one of
the following settings:

standard

The default option. Synchronous file system transactions are
written to the intent log and then all devices written are
flushed to ensure the data is stable (that is, not cached by
device controllers).

always

Every file system transaction would be written and flushed to
stable storage. This setting should be used only where extreme
caution is required, as there is a significant performance
penalty.

disabled

Synchronous requests are disabled. File system transactions
commit to stable storage only on the next DMU transaction group
commit, which might be after many seconds. This setting gives
the highest performance. However, it is very dangerous as ZFS
would be ignoring the synchronous transaction demands of appli‐
cations such as databases or NFS. Furthermore, when this set‐
ting is in effect for the currently active root or /var
filesystem, out-of-spec behavior, application data loss, and
increased vulnerability to replay attacks can result. Adminis‐
trators should only use this option only when these risks are
understood.

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 snap‐
shots 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 her quota before the system
notices that she is over quota. The system would then begin to
refuse additional writes with the EDQUOT error message . See the
zfs 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 privi‐
lege 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:

o POSIX name (for example, joe)

o POSIX numeric ID (for example, 789)

o SID name (for example, joe.smith@mydomain)

o SID numeric ID (for example, S-1-123-456-789)

version=1 | 2 | current

The on-disk version of this file system, which is independent of
the pool version. This property can only be set to later supported
versions. See the zfs upgrade command.

volsize=size

Specifies the logical size of the volume. By default, creating a
volume establishes a refreservation that is a somewhat larger than
the actual logical volume size, to account for ZFS metadata over‐
head. Any changes to volsize are reflected in an equivalent change
to the refreservation. The volsize can only be set to a multiple of
volblocksize, and cannot be zero.

The refreservation is set on the volume to prevent unexpected
behavior for consumers. Without the reservation, the volume could
run out of space, resulting in undefined behavior or data corrup‐
tion, depending on how the volume is used. These effects can also
occur when the volume size is changed while it is in use (particu‐
larly 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 cre‐
ate -V command. 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 reserva‐
tion.

vscan=on | off

Controls whether regular files should be scanned for viruses when a
file is opened and closed. In addition to enabling this property,
the virus scan service must also be enabled for virus scanning to
occur. The default value is off.

xattr=on | off

Controls whether extended attributes are enabled for this file sys‐
tem. The default value is on.

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.

The following three properties cannot be changed after the file system
is created, and therefore, should be set when the file system is cre‐
ated. If the properties are not set with the zfs create or zpool create
commands, 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

Indicates whether the file name matching algorithm used by the file
system should be case-sensitive, case-insensitive, or allow a com‐
bination of both styles of matching. The default value for the cas‐
esensitivity property is mixed. Traditionally, UNIX and POSIX file
systems have case-sensitive file names.

The mixed value for the casesensitivity property indicates that the
file system can support requests for both case-sensitive and case-
insensitive matching behavior. Currently, case-insensitive matching
behavior on a file system that supports mixed behavior is limited
to the Solaris SMB server product. For more information about the
mixed value behavior, see the Solaris ZFS Administration Guide.

Note -

This SMB-related property is not fully functional in the Oracle
Solaris 10 release because the Oracle Solaris SMB server is not
supported in the Oracle Solaris 10 release.

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 normal‐
ization property is none. This property cannot be changed after the
file system is created.

Note -

This SMB-related property is not fully functional in the Oracle
Solaris 10 release because the Oracle Solaris SMB server is not
supported in the Oracle Solaris 10 release.

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.

Note -

This SMB-related property is not fully functional in the Oracle
Solaris 10 release because the Oracle Solaris SMB server is not
supported in the Oracle Solaris 10 release.

Temporary Mount Point Properties
When a ZFS file system is mounted, either through the legacy mount(1M)
command for legacy mounts or the zfs mount command, 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
rstchown rstchown/norstchown

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 val‐
ues 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. For prop‐
erties other than mountpoint, if the properties are changed while the
dataset is mounted, the new setting overrides any temporary settings.
The mountpoint property cannot be changed while a temporary mountpoint
property is in effect (that is, while the dataset is mounted at a tem‐
porary location).

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, num‐
bers, 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 sug‐
gested 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.

The values of user properties are arbitrary strings, are always inher‐
ited, and are never validated. All of the commands that operate on
properties (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 limited to 1024 characters.

ZFS Volumes as Swap or Dump Devices
During an initial installation or a live upgrade from a UFS file sys‐
tem, a swap device and dump device are created on ZFS volumes in the
ZFS root pool. The default swap device varies based on the amount of
the system's physical memory.The size of the dump device depends on the
kernel's requirements at installation time. Separate ZFS volumes must
be used for the swap area and dump devices. Do not swap to a file on a
ZFS file system. A ZFS swap file configuration is not supported.

If you need to change your swap area or dump device after the system is
installed or upgraded, use the swap(1M) and dumpadm(1M) commands. If
you need to change the size of your swap area or dump device, see the
Solaris ZFS Administration Guide.

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

zfs ?

Displays a help message.

zfs help subcommand | help property property | permission

Displays zfs subcommand usage information. You can display help for
a specific subcommand, property, or delegated permission. If you
display help for a specific subcommand or property, the subcommand
syntax or property value is displayed. Using zfs help without any
arguments displays a complete list of zfs subcommands.

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
parent.

-p

Creates all the non-existing parent datasets. Datasets created
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 operation com‐
pletes successfully.

-o property=value

Sets the specified property as if the command zfs set prop‐
erty=value was invoked at the same time the dataset was cre‐
ated. 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 [-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/{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.

-p

-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 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 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

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 sys‐
tems outside the target hierarchy.

-f

Force an unmount of any file systems using the unmount -f com‐
mand. 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 destroy [-rRd] snapshot

The given snapshot is 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 the 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.

-d

Defer snapshot deletion.

-r

Destroy (or mark for deferred deletion) all snapshots with this
name in descendent file systems.

-R

Recursively destroy all dependents.

zfs snapshot [-r] [-o property=value] ... filesystem@snapname|vol‐
ume@snapname

Creates a snapshot with the given name. All previous modifications
by successful system calls to the file system are part of the snap‐
shot. zfs snap can be used as an alias for zfs snapshot. See the
"Snapshots" section for details.

-r

Recursively create snapshots of all descendent datasets. Snap‐
shots are taken atomically, so that all recursive snapshots
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
discarded, and the dataset reverts to the state at the time of the
snapshot. By default, the command refuses to roll back to a snap‐
shot other than the most recent one. In order to do so, all inter‐
mediate snapshots must be destroyed by specifying the -r option.

The -rR options do not recursively destroy the child snapshots of a
recursive snapshot. Only the top-level recursive snapshot is
destroyed by either of these options. To completely roll back a
recursive snapshot, you must rollback the individual child snap‐
shots.

-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
hierarchy, and is created as the same type as the original.

-p

Creates all the non-existing parent datasets. Datasets created
in this manner are automatically mounted according to the
mountpoint property inherited from their parent. If the target
file system 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
relationship 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.

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.

-p

Creates all the nonexistent parent datasets. Datasets created
in this manner are automatically mounted according to the
mountpoint property inherited from their parent.

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 abso‐
lute pathname or the relative pathname. By default, all file sys‐
tems and volumes are displayed. Snapshots are displayed if the
listsnaps property is on (the default is on) . The following fields
are displayed, name,used,available,referenced,mountpoint.

-H

Used for scripting mode. Do not print headers and separate
fields by a single tab instead of arbitrary white space.

-r

Recursively display any children of the dataset on the command
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.

-o property

A comma-separated list of properties to display. The property
must be:

o One of the properties described in the "Native Prop‐
erties" section

o A user property

o The value name to display the dataset name

o The value space to display space usage properties on
file systems and volumes. This is a shortcut for
specifying the syntax:

-o name,avail,used,usedsnap,usedds,usedrefreserv,\
usedchild -t filesystem,volume

-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" section, or the
special value name to sort by the dataset name. Multiple prop‐
erties 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 order‐
ing.

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

-S property

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 , volume, or all. For example, specify‐
ing -t snapshot displays only snapshots. The following aliases
can be used in place of the type specifiers: fs (filesystem),
snap (snapshot), and vol (volume).

zfs set [-r] 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-
readable form with a suffix of B, K, M, G, T, P, E, Z (for bytes,
kilobytes, megabytes, gigabytes, terabytes, petabytes, exabytes, or
zettabytes, respectively). User properties can be set on snapshots.
For more information, see the "User Properties" section.

-r

Recursively apply the effective value of the setting throughout
the subtree of child datasets. The effective value may be set
or inherited, depending on the property.

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 except the RECEIVED column are displayed by default;
specify particular or all columns, 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 snap‐
shot).

-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.

-o field

Set of fields to display. One or more of:

name,property,value,received,source

Present multiple fields as a comma-separated list. The default
value is:

name,property,value,source

The keyword all specifies all sources.

-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,received,none

The default value is all sources.

-p

Display numbers in parseable (exact) values.

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 values, and details on which properties can be inherited.

-r

Recursively inherit the given property for all children.

-S

Revert to the received property value, if any. If the property
does not have a received value, the behavior of zfs inherit -S
is the same as zfs inherit without -S. If the property does
have a received value, zfs inherit masks the received value
with the inherited value until zfs inherit -S reverts to the
received value.

zfs upgrade

Identifies a file system version, which determines available file
system features in the currently running software release. You can
continue to use older file system versions, but some features might
not be available. A file system can be upgraded by using the zfs
upgrade -a command. You will not be able to access a file system of
a later version on a system that runs an earlier software version.

zfs upgrade [-v]

Displays ZFS file system versions that are supported by the current
software. The current ZFS file system versions and all previously
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. Upgrading a file
system means that it will no longer be accessible on a system run‐
ning an older software version. A zfs send stream that is generated
from a new file system snapshot cannot be accessed on a system that
runs an older software version.

In general, the file system version is independent of the pool ver‐
sion. See zpool(1M) 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.

-a

Upgrade all file systems on all imported pools.

filesystem

Upgrade the specified file system.

-r

Upgrade the specified file system and all descendent file sys‐
tems

-V version

Upgrade to the specified version. If the -V flag is not speci‐
fied, 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.

zfs userspace [-hniHp] [-o field[,...]] [-sS field]... [-t type [,...]]
filesystem | snapshot

Displays space consumed by, and quotas on, each user in the speci‐
fied filesystem or snapshot. This corresponds to the userused@user
and userquota@user properties.

-h

Displays syntax help message and exit.

-n

Displays numeric ID instead of user/group name.

-H

Does not print headers, use tab-delimited output.

-p

Uses exact (parseable) numeric output.

-o field[,...]

Displays only the specified fields from the following set,
type,name,used,quota. The default is to display all fields.

-s field

Sorts output by the specified field. The s and S flags may be
specified multiple times to sort first by one field, then by
another. The default is -s type -s name.

-S field

Sorts by this field in reverse order. See -s.

-t type[,...]

Displays 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

Translates SID to POSIX ID. The POSIX ID may be ephemeral if no
mapping exists. Normal POSIX interfaces (for example, stat(2),
ls -l) perform this translation, so the -i option allows the
output from zfs userspace to be compared directly with those
utilities. However, -i may lead to confusion if some files were
created by an SMB user before a SMB-to-POSIX name mapping was
established. In such a case, some files are owned by the SMB
entity and some by the POSIX entity. However, the -i option
will report that the POSIX entity has the total usage and quota
for both.

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 posix‐
group,smbgroup.

zfs mount

Displays all ZFS file systems currently mounted.

zfs mount [-vO] [-o options] -a | filesystem

Mounts ZFS file systems. Invoked automatically as part of the boot
process.

-o options

An optional, comma-separated list of mount options to use tem‐
porarily 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.

-v

Report mount progress.

-a

Mount all available ZFS file systems. Invoked automatically as
part of the boot process.

filesystem

Mount the specified filesystem.

zfs unmount [-f] -a | filesystem|mountpoint

Unmounts currently mounted ZFS file systems. Invoked automatically
as part of the shutdown process.

-f

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

-a

Unmount all available ZFS file systems. Invoked automatically
as part of the boot process.

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 or sharesmb property
set. Sharing a file system with the NFS or SMB protocol means that
the file system data is available over the network. ZFS file sys‐
tems that have the sharenfs or sharesmb property set are automati‐
cally shared when a system is booted.

-a

Shares all ZFS file systems that have the sharenfs or sharesmb
property set and according to the share property values.

filesystem

Shares the specified file system that has the sharenfs or
sharesmb property set and according to the share property val‐
ues.

zfs unshare -a | filesystem|mountpoint

Unshares all ZFS file systems that have the sharenfs or sharesmb
property set.

-a

Unshare all available ZFS file systems. Invoked automatically
as part of the boot process.

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 [-Rbpv] [-[iI] snapshot] snapshot
zfs send -r [-bcpv] [-[i] snapshot] snapshot

Creates a stream representation of the second snapshot, 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.

-b

Sends only received property values whether or not they are
overridden by local settings, but only if the dataset has ever
been received. Use this option when you want zfs receive to
restore received properties backed up on the sent dataset and
to avoid sending local settings that may have nothing to do
with the source dataset, but only with how the data is backed
up.

-c

Creates a self-contained stream. A self-contained stream is one
that is not dependent on any datasets not included in the
stream package. Valid only with the -r option. If used with the
-i option, the stream is dependent on the snapshot specified as
an argument to the that option.

See the "ZFS Streams" section of the ZFS Administration Guide
for details.

-i snapshot

Generates an incremental stream from the first snapshot to the
second snapshot. The incremental source (the first 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 second 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

Generates a stream package that sends all intermediary snap‐
shots from the first snapshot to the second 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

Generates a replication stream package that replicates the
specified file system, and all descendent file systems, up to
the named snapshot. When received, all properties, snapshots,
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 sys‐
tems that do not exist on the sending side are destroyed.

-r

Generates a recursive stream package. A recursive stream pack‐
age contains a series of full and/or incremental streams. When
received, all properties and descendent file systems are pre‐
served. Unlike with the replication stream packages generated
with the -R flag, intermediate snapshots are not preserved
unless the intermediate snapshot is the origin of a clone that
is included in the stream.

If the -i option is used in conjunction with the -r option, an
incremental recursive stream is generated. The current values
of properties as well as current snapshot and file system names
are set when the stream is received. If the -F option is speci‐
fied when this stream is received, snapshots and file systems
that do not exist on the sending side are destroyed. The -I
option cannot be used in conjunction with the -r option.

When combined with the -c option, a self-contained recursive
stream package is created. If both the -c and -i options are
used, file systems and volumes that do not have the snapshot
specified with the -i option are sent as self-contained
streams.

See the "ZFS Streams" section of the ZFS Administration Guide
to understand how a recursive stream package differs from a
replication stream package.

-p

Sends properties.

-v

Displays verbose information about the stream package gener‐
ated.

The format of the stream is committed. You will be able to receive
your streams on future versions of ZFS.

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. 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. If -o property=value or -x property is speci‐
fied, it applies to the effective value of the property throughout
the entire subtree of replicated datasets. Effective property val‐
ues may be set or inherited, depending on the property and whether
the dataset is the topmost in the replicated subtree. Received
properties are retained in spite of being overridden and may be
restored with zfs inherit -rS or zfs send -Rb.

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 spec‐
ified 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 specified, only the tail of the sent snapshot path is
appended (for example, 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

Uses all but the first element of the sent snapshot path (all
but the pool name) to determine the name of the new snapshot as
described in the paragraph above.

-e

Uses the last element of the sent snapshot path to determine
the name of the new snapshot as described in the paragraph
above.

-F

Forces 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 -[iI]), destroy snapshots and file systems that do
not exist on the sending side.

-n

Do not actually receive the stream. This can be useful in con‐
junction with the -v option to verify the name the receive
operation would use.

-o property=value

Sets the specified property as if the command zfs set prop‐
erty=value is invoked at the same time the received dataset is
created from the non-incremental send stream or updated from
the incremental send stream. Any editable ZFS property can also
be set at receive time. Set-once properties bound to the
received data, such as normalization and casesensitivity, can‐
not be set at receive time even when the datasets are newly
created by zfs receive. Multiple -o options can be specified.
An error results if the same property is specified in multiple
-o or -x options.

-u

File system that is associated with the received stream is not
mounted.

-v

Prints verbose information about the stream and the time
required to perform the receive operation.

-x property

Ensures that the effective value of the specified property
after the receive is unaffected by the value of that property
in the send stream (if any), as if the property had been
excluded from the send stream. If the specified property is not
present in the send stream, this option does nothing. If a
received property needs to be overridden, the effective value
can be set or inherited, depending on the property. In the case
of an incremental update, -x leaves any existing local setting
or explicit inheritance unchanged (since the received property
is already overridden). All -o restrictions apply equally to
-x.

zfs allow filesystem | volume

Delegates ZFS administration permissions for the specified file
system to non-privileged users. See the other forms of zfs allow
for more information.

Delegates ZFS administration permission for the file systems to
non-privileged users.

[-ug] everyone|user|group[,...]

Specifies to whom the permissions are delegated. Multiple enti‐
ties can be specified as a comma-separated list. If neither 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 options.

[-e] perm|@setname[,...]

Specifies that the permissions be delegated to everyone. Multi‐
ple 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:

# zfs help permissions
The following delegated permissions are supported:

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
diff subcommand Allows lookup of paths within a dataset,
given an object number. Ordinary users
need this
in order to use zfs diff
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 Allows rolling back datasets to
previously-taken snapshots
send subcommand Allows sending of snapshots
share subcommand Allows sharing file systems over NFS or
SMB protocols
snapshot subcommand Allows taking of snapshots
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

The following properties can have delegated permissions applied:
aclinherit aclmode atime canmount
casesensitivity checksum compression copies
devices exec logbias mountpoint
nbmand normalization primarycache quota
readonly recordsize refquota refreservation
reservation rstchown secondarycache setuid
shareiscsi sharenfs sharesmb snapdir
sync utf8only version volblocksize
volsize vscan xattr zoned

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 sys‐
tem.

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 nam‐
ing restrictions as ZFS file systems, but the name must begin with
an at (@) sign , and can be no more than 64 characters long.

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 names‐
pace, 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 return EBUSY.

-r

Specifies that a hold with the given tag is applied recursively
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 snapshots,
in addition to listing the holds on the named snapshot.

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.

If a hold exists on a snapshot, attempts to destroy that snapshot
by using the zfs destroy command return EBUSY.

-r

Recursively releases a hold with the given tag on the snapshots
of all descendent file systems.

zfs diff [-FHte] [-o field] ... snapshot snapshot | filesystem
zfs diff -E[-FHt] -o field ... snapshot | filesystem

Gives a high-level description of the differences between a snap‐
shot and a descendent dataset. The descendent can be either a snap‐
shot of the dataset or the current dataset.

If a single snapshot is specified, then differences between that
snapshot and the current dataset are given.

For each file that has undergone a change between the original
snapshot and the descendent, the type of change is described along
with the name of the file. In the case of a rename, both the old
and new names are shown. Whitespace characters, backslash charac‐
ters, and other non-printable or non-7-bit ASCII characters found
in file names are displayed as a backslash character followed by
the three-digit octal representation of the byte value.

If the -t option is specified, the first column of output from the
command is the file's st_ctim value. For deleted files, this is the
final st_ctim in the earlier snapshot.

The type of change follows any timestamp displayed, and is
described with a single character:

+ Indicates the file was added in the later dataset.

- Indicates the file was removed in the later dataset.

M Indicates the file was modified in the later dataset.

R Indicates the file was renamed in the later dataset.

If the -F option is specified, the next column of output is a sin‐
gle character describing the type of the file. The mappings are:

F regular file

/ directory

B block device

> door

| FIFO

@ symbolic link

P event portal

= socket

If the modification involved a change in the link count of a non-
directory file, the change is expressed as a delta within parenthe‐
ses on the modification line. If the file was renamed, the old name
is separated from the new with the string "->".

If the -H option is selected, easier-to-parse output is produced.
Fields are separated by a single tab, and no arrow string (->) is
placed between the old and new names of a rename. No guarantees are
made on the spacing between fields of non -H output.

If the -e option is selected, then all files added or modified
between the two snapshots are enumerated and no deleted files are
displayed. The change type always reports as + regardless of the
type of modification.

If the -E option is selected, then differences are given as if from
an empty snapshot to the specified snapshot or dataset.

If the -o field option is selected, then only selected fields are
displayed. Each line starts with the standard fields requested by
the -F and -t options, followed by the fields requested in succes‐
sive -o options. As with the -H option, all fields are separated by
a single tab. The allowable field names include:

object The number printed by ls -i for the file

parent The number printed by ls -i for the file

size The file size as displayed by ls -s

links The number of links to the file

linkschange The change in the number of links to the file

name The name of the file

oldname The name of the file before the rename, or —
(hyphen) if the file was not renamed

user The owner name of the file as displayed by ls

group The group name of the file as displayed by ls

ctime The timestamp when the file's metadata was last mod‐
ified

mtime The timestamp when the file was last modified

atime The timestamp when a file was last accessed

crtime The timestamp when a file was created

Unless they already have the {PRIV_SYS_CONFIG} or {PRIV_SYS_MOUNT}
privilege, users must be granted the diff permission with zfs allow
to use this subcommand.

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 is 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 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 compres‐
sion 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 on. See zpool(1M) for more information on pool properties.

# zfs list
NAME USED AVAIL REFER MOUNTPOINT
pool 450K 457G 18K /pool
pool/home 315K 457G 21K /export/home
pool/home/anne 18K 457G 18K /export/home/anne
pool/home/bob 276K 457G 276K /export/home/bob

Example 6 Setting a Quota on a ZFS File System

The following command sets a quota of 30 GB for pool/home/bob.

# zfs set quota=30G 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 Wed Jun 6 15:16 2012 -
pool/home/bob used 31K -
pool/home/bob available 30.0G -
pool/home/bob referenced 31K -
pool/home/bob compressratio 1.00x -
pool/home/bob mounted yes -
pool/home/bob quota 30G 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 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 zoned 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 shareiscsi off 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 mixed -
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 31K -
pool/home/bob usedbychildren 0 -
pool/home/bob usedbyrefreservation 0 -
pool/home/bob logbias latency default
pool/home/bob sync standard default
pool/home/bob rekeydate - default
pool/home/bob rstchown 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/home/bob quota 30G
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
# 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@aand
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@4daysago @5daysago
# zfs rename -r pool/users@3daysago @4daysago
# zfs rename -r pool/users@2daysago @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 example shows how to share a file system with nosuid
access. In this case, single quotes are not needed for the share prop‐
erty value because a single share option is included.

# zfs set sharenfs=nosuid tank/shares

The following commands show how to set sharenfs property options to
enable rw access for a set of IP addresses and to enable root access
for system neo on the tank/home file system. In this case, single
quotes are required for multiple options.

# zfs set sharenfs='rw=@123.123.0.0/16,root=neo' tank/home

If you are using DNS for host name resolution, specify the fully quali‐
fied hostname.

Example 17 Delegating ZFS Administration Permissions on a ZFS Dataset

The following example shows how to set permissions so that user anne
can create, destroy, mount, and take snapshots on pool/home/anne. The
permissions on pool/home/anne are also displayed.

# zfs allow anne create,destroy,mount,snapshot pool/home/anne
# zfs allow pool/home/anne
---- Permissions on pool/home/anne -----------------------------------
Local+Descendent permissions:
user anne create,destroy,mount,snapshot

Because the pool/home/anne mount point permission is set to 755 by
default, user anne will be unable to mount file systems under
pool/home/anne. Set an ACL similar to the following syntax to provide
mount point access:

# chmod A+user:anne:add_subdirectory:allow /pool/home/anne

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 pool/home. This syntax also allows staff members
to destroy their own file systems, but not destroy anyone else's file
system. The permissions on pool/home are also displayed.

# zfs allow staff create,mount pool/home
# zfs allow -c destroy pool/home
# zfs allow pool/home
---- Permissions on pool/home ----------------------------------------
Create time permissions:
destroy
Local+Descendent permissions:
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 pool/home file system. The permissions on pool/home are also dis‐
played.

# zfs allow -s @pset create,destroy,snapshot,mount pool/home
# zfs allow staff @pset pool/home
# zfs allow pool/home
---- Permissions on pool/home ----------------------------------------
Permission sets:
@pset create,destroy,mount,snapshot
Create time permissions:
destroy
Local+Descendent permissions:
group staff @pset,create,mount

Example 20 Delegating Property Permissions on a ZFS Dataset

The following example shows how to grant the ability to set quotas and
reservations on the tank/users file system. The permissions on
tank/users are also displayed.

# zfs allow mark quota,reservation tank/users
# zfs allow tank/users
---- Permissions on tank/users ---------------------------------------
Local+Descendent permissions:
user mark quota,reservation

mark% zfs set quota=10G tank/users/tim
mark% zfs get quota tank/users/tim
NAME PROPERTY VALUE SOURCE
tank/users/tim 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 @pset permission set for the staff group on the pool/home file sys‐
tem. The permissions on pool/home are also displayed.

# zfs unallow -s @pset snapshot pool/home
# zfs allow pool/home
---- Permissions on pool/home ----------------------------------------
Permission sets:
@pset create,destroy,mount
Create time permissions:
destroy
Local+Descendent permissions:
group staff @pset,create,mount

Example 22 Displaying ZFS Snapshot Differences

The following command shows the output from a zfs diff command with the
-F and -t options.

# zfs diff -Ft myfiles@snap1
1269962501.206726811 M / /myfiles/
1269962444.207369955 M F /myfiles/link_to_me (+1)
1269962499.207519034 R /myfiles/rename_me -> /myfiles/renamed
1269962431.813566720 - F /myfiles/delete_me
1269962518.666905544 + F /myfiles/new_file
1269962501.393099817 + | /myfiles/new_pipe

EXIT STATUS
The following exit values are returned:

Successful completion.

An error occurred.

Invalid command line options were specified.

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

┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Availability │system/file-system/zfs │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │Committed │
└─────────────────────────────┴─────────────────────────────┘

SEE ALSO
chown(1), pktool(1), ssh(1), mount(1M), share(1M), unshare(1M),
zonecfg(1M), zpool(1M), chmod(2), chown(2), stat(2), write(2),
fsync(3C), dfstab(4), attributes(5)

See the gzip(1) man page, which is not part of the SunOS man page col‐
lection.

For information about using the ZFS web-based management tool and other
ZFS features, see the Solaris ZFS Administration Guide.

NOTES
A file described as modified by the diff subcommand might have been
modified in multiple ways. Any action that causes a change in the
st_ctim (see stat(2)) is a basis for reporting a modification.

SunOS 5.10 13 Jun 2012 zfs(1M)

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