Provided by: zfs-fuse_0.7.0-20_amd64 
NAME
zfs - configures ZFS file systems
SYNOPSIS
zfs [-?]
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 property=value filesystem|volume|snapshot ...
zfs get [-r|-d depth][-Hp][-o all | field[,...]] [-s source[,...]]
all | property[,...] filesystem|volume|snapshot ...
zfs inherit [-rS] property filesystem|volume|snapshot ...
zfs upgrade [-v]
zfs upgrade [-r] [-V version] -a | filesystem
zfs userspace [-niHp] [-o field[,...]] [-sS field] ...
[-t type [,...]] filesystem|snapshot
zfs groupspace [-niHp] [-o field[,...]] [-sS field] ...
[-t type [,...]] filesystem|snapshot
zfs mount
zfs mount [-vO] [-o options] -a | filesystem
zfs unmount [-f] -a | filesystem|mountpoint
zfs share -a | filesystem
zfs unshare -a filesystem|mountpoint
zfs send [-DvRp] [-[iI] snapshot] snapshot
zfs receive [-vnFu] filesystem|volume|snapshot
zfs receive [-vnFu] [-d | -e] filesystem
zfs allow filesystem|volume
zfs allow [-ldug] "everyone"|user|group[,...] perm|@setname[,...]
filesystem|volume
zfs allow [-ld] -e perm|@setname[,...] filesystem|volume
zfs allow -c perm|@setname[,...] filesystem|volume
zfs allow -s @setname perm|@setname[,...] filesystem|volume
zfs unallow [-rldug] "everyone"|user|group[,...] [perm|@setname[,... ]]
filesystem|volume
zfs unallow [-rld] -e [perm|@setname[,... ]] filesystem|volume
zfs unallow [-r] -c [perm|@setname[ ... ]] filesystem|volume
zfs unallow [-r] -s @setname [perm|@setname[,... ]] filesystem|volume
zfs hold [-r] tag snapshot...
zfs holds [-r] snapshot...
zfs release [-r] tag snapshot...
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 systems 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 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 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, 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 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 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 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 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.
Deduplication
Deduplication is the process for removing redundant data at the block-level, reducing the total amount
of data stored. If a file system has the dedup property enabled, duplicate data blocks are removed
synchronously. The result is that only unique data is stored and common components are shared among
files.
Native Properties
Properties are divided into two types, native properties and user-defined (or "user") properties. Native
properties either export internal 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, below.
Every dataset has a set of properties that export statistics about the dataset as well as control various
behaviors. Properties are inherited from the parent unless overridden by the child. Some properties apply
only to certain types of datasets (file systems, volumes, or snapshots).
The values of numeric properties can be specified using human-readable suffixes (for example, k, KB, M,
Gb, and so forth, up to Z for zettabyte). The following are all valid (and equal) specifications:
1536M, 1.5g, 1.50GB
The values of non-numeric properties are case sensitive and must be 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 compression=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 property 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.
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 descendents. 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 descendent datasets. 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 various 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 descendents).
usedbyrefreservation
The amount of space used by a refreservation set on this dataset, which would be freed if the
refreservation was removed.
usedbysnapshots
The amount of space consumed by snapshots of this dataset. In particular, it is the amount of space
that would be freed if all of this dataset's snapshots were destroyed. Note that this is not simply
the sum of the snapshots' used properties because space can be shared by multiple snapshots.
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.
groupused@group
The amount of space consumed by the specified group in this dataset. Space is charged to the group of
each file, as displayed by ls -l. See the userused@user property for more information.
Unprivileged users can only access their own groups' space usage. The root user, or a user who has
been granted the groupused privilege with zfs allow, can access all groups' usage.
volblocksize=blocksize
For volumes, specifies the block size of the volume. The blocksize cannot be changed once the volume
has been written, so it should be set at volume creation time. The default blocksize for volumes is 8
Kbytes. Any power of 2 from 512 bytes to 128 Kbytes is valid.
This property can also be referred to by its shortened column name, volblock.
The following native properties can be used to change the behavior of a ZFS dataset.
aclinherit=discard | noallow | restricted | passthrough | passthrough-x
Controls how ACL entries are inherited when files and directories are created. A file system with an
aclinherit property of discard does not inherit any ACL entries. A file system with an aclinherit
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 the owner@, group@, and everyone@ 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.
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 are made to the ACL other than generating the necessary ACL entries to represent the new mode
of the file or directory.
atime=on | off
Controls whether the access time for files is updated when they are read. Turning this property off
avoids producing write traffic when reading files and can result in significant performance gains,
though it might confuse mailers and other similar utilities. The default value is on.
canmount=on | off | noauto
If this property is set to off, the file system cannot be mounted, and is ignored by zfs mount -a.
Setting this property to off is similar to setting the mountpoint property to none, except that the
dataset still has a normal mountpoint property, which can be inherited. 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.
compression=on | off | lzjb | gzip | gzip-N | zle
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 property and counting against quotas and reservations.
Changing this property only affects newly-written data. Therefore, set this property at file system
creation time by using the -o copies=N option.
dedup=on | off | verify | sha256[,verify]
Controls whether deduplication is in effect for a dataset. The default value is off. The default
checksum used for deduplication is sha256 (subject to change). When dedup is enabled, the dedup
checksum algorithm overrides the checksum property. Setting the value to verify is equivalent to
specifying sha256,verify.
If the property is set to verify, then, whenever two blocks have the same signature, ZFS will do a
byte-for-byte comparison with the existing block to ensure that the contents are identical.
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.
mlslabel=label | none
The mlslabel property is a sensitivity label that determines if a dataset can be mounted in a zone
on a system with Trusted Extensions enabled. If the labeled dataset matches the labeled zone, the
dataset can be mounted and accessed from the labeled zone.
When the mlslabel property is not set, the default value is none. Setting the mlslabel property to
none is equivalent to removing the property.
The mlslabel property can be modified only when Trusted Extensions is enabled and only with
appropriate privilege. Rights to modify it cannot be delegated. When changing a label to a higher
label or setting the initial dataset label, the {PRIV_FILE_UPGRADE_SL} privilege is required. When
changing a label to a lower label or the default (none), the {PRIV_FILE_DOWNGRADE_SL} privilege is
required. Changing the dataset to labels other than the default can be done only when the dataset is
not mounted. When a dataset with the default label is mounted into a labeled-zone, the mount
operation automatically sets the mlslabel property to the label of that zone.
When Trusted Extensions is not enabled, only datasets with the default label (none) can be mounted.
mountpoint=path | none | legacy
Controls the mount point used for this file system. See the "Mount Points" section for more
information on how this property is used.
When the mountpoint property is changed for a file system, the file system and any children that
inherit the mount point are unmounted. If the new value is legacy, then they remain unmounted.
Otherwise, they are automatically remounted in the new location if the property was previously legacy
or none, or if they were mounted before the property was changed. In addition, any shared file
systems are unshared and shared in the new location.
nbmand=on | off
Controls whether the file system should be mounted with nbmand (Non Blocking mandatory locks). This
is used for CIFS 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 property is set to all, then both user
data and metadata is cached. If this property is set to none, then neither user data nor metadata is
cached. If this property is set to metadata, then only metadata is cached. The default value is all.
quota=size | none
Limits the amount of space a dataset and its descendents can consume. This property enforces a hard
limit on the amount of space used. This includes all space consumed by descendents, including file
systems and snapshots. Setting a quota on a descendent of a dataset that already has a quota does not
override the ancestor's quota, but rather imposes an additional limit.
Quotas cannot be set on volumes, as the volsize property acts as an implicit quota.
userquota@user=size | none
Limits the amount of space consumed by the specified user. Similar to the refquota property, the
userquota space calculation does not include space that is used by descendent datasets, such as
snapshots and clones. User space consumption is identified by the userspace@user property.
Enforcement of user quotas may be delayed by several seconds. This delay means that a user might
exceed 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 privilege with zfs allow, can get and set everyone's quota.
This property is not available on volumes, on file systems before version 4, or on pools before
version 15. The userquota@... 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)
groupquota@group=size | none
Limits the amount of space consumed by the specified group. Group space consumption is identified by
the userquota@user property.
Unprivileged users can access only their own groups' space usage. The root user, or a user who has
been granted the groupquota privilege with zfs allow, can get and set all groups' quotas.
readonly=on | off
Controls whether this dataset can be modified. The default value is off.
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 size specified must be a power of two greater than or equal to 512 and less than or equal to 128
Kbytes.
Changing the file system's recordsize affects only files created afterward; existing files are
unaffected.
This property can also be referred to by its shortened column name, recsize.
refquota=size | none
Limits the amount of space a dataset can consume. This property enforces a hard limit on the amount
of space used. This hard limit does not include space used by descendents, including file systems and
snapshots.
refreservation=size | none
The minimum amount of space guaranteed to a dataset, not including its descendents. When the amount
of space used is below this value, the dataset is treated as if it were taking up the amount of space
specified by refreservation. The refreservation reservation is accounted for in the parent datasets'
space used, and counts against the parent datasets' quotas and reservations.
If refreservation is set, a snapshot is only allowed if there is enough free pool space outside of
this reservation to accommodate the current number of "referenced" bytes in the dataset.
This property can also be referred to by its shortened column name, refreserv.
reservation=size | none
The minimum amount of space guaranteed to a dataset and its descendents. When the amount of space
used is below this value, the dataset is treated as if it were taking up the amount of space
specified by its reservation. Reservations are accounted for in the parent datasets' space used, and
count against the parent datasets' quotas and reservations.
This property can also be referred to by its shortened column name, reserv.
secondarycache=all | none | metadata
Controls what is cached in the secondary cache (L2ARC). If this property is set to all, then both
user data and metadata is cached. If this property is set to none, then neither user data nor
metadata is cached. If this property is set to metadata, then only metadata is cached. The default
value is all.
setuid=on | off
Controls whether the set-UID bit is respected for the file system. The default value is on.
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. However, setting this property on a file system has no direct effect.
sharesmb=on | off | opts
Controls whether the file system is shared by using the Solaris CIFS 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 sharemgr(1M). 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 sharemgr(1M) command is invoked
with no options. Otherwise, the sharemgr(1M) command is invoked with options equivalent to the
contents of this property.
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
specified 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/backups, 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.
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.
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.
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.
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
For volumes, specifies the logical size of the volume. By default, creating a volume establishes a
reservation of equal size. For storage pools with a version number of 9 or higher, a refreservation
is set instead. Any changes to volsize are reflected in an equivalent change to the reservation (or
refreservation). The volsize can only be set to a multiple of volblocksize, and cannot be zero.
The reservation is kept equal to the volume's logical size to prevent unexpected behavior for
consumers. Without the reservation, the 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.
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 system. 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 created. 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 combination of both styles of matching. The default value for the
casesensitivity property is sensitive. 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 CIFS server product.
For more information about the mixed value behavior, see the Solaris ZFS Administration Guide.
normalization = none | formC | formD | formKC | formKD
Indicates whether the file system should perform a unicode normalization 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 property
is automatically set to on. The default value of the normalization property is none. This property
cannot be changed after the file system is created.
utf8only=on | off
Indicates whether the file system should reject file names that include characters that are not
present in the UTF-8 character code set. If this property is explicitly set to off, the normalization
property must either not be explicitly set or be set to none. The default value for the utf8only
property is off. This property cannot be changed after the file system is created.
The casesensitivity, normalization, and utf8only properties are also new permissions that can be assigned
to non-privileged users by using the ZFS delegated administration feature.
Temporary Mount Point Properties
When a file system is mounted, either through mount(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
(file systems, volumes, and snapshots).
User property names must contain a colon (:) character to distinguish them from native properties. They
may contain lowercase letters, numbers, and the following punctuation characters: colon (:), dash (-),
period (.), and underscore (_). The expected convention is that the property name is divided into two
portions such as module:property, but this namespace is not enforced by ZFS. User property names can be
at most 256 characters, and cannot begin with a dash (-).
When making programmatic use of user properties, it is strongly suggested to use a reversed DNS domain
name for the module component of property names to reduce the chance that two independently-developed
packages use the same property name for different purposes. Property names beginning with com.sun. are
reserved for use by Sun Microsystems.
The values of user properties are arbitrary strings, are always inherited, 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 system, a swap device and dump device
are created on ZFS volumes in the ZFS root pool. By default, the swap area size is based on 1/2 the size
of physical memory up to 2 Gbytes. 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 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 completes successfully.
-o property=value
Sets the specified property as if the command zfs set property=value was invoked at the same time
the dataset was created. Any editable ZFS property can also be set at 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
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 completes successfully.
-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 systems outside the target hierarchy.
-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 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|volume@snapname
Creates a snapshot with the given name. All previous modifications by successful system calls to the
file system are part of the snapshot. See the "Snapshots" section for details.
-r
Recursively create snapshots of all descendent datasets. Snapshots are taken atomically, so that
all recursive 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 snapshot other than the most recent one.
In order to do so, all intermediate 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 snapshots.
-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
filesystem or volume already exists, the operation completes successfully.
-o property=value
Sets the specified property; see zfs create for details.
zfs promote clone-filesystem
Promotes a clone file system to no longer be dependent on its "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 snapshot that was cloned, and any snapshots previous to this snapshot, are now owned by the
promoted clone. The space they use moves from the origin file system to the promoted clone, so enough
space must be available to accommodate these snapshots. No new space is consumed by this operation,
but the space accounting is adjusted. The promoted clone must not have any conflicting snapshot names
of its own. The rename subcommand can be used to rename any conflicting snapshots.
zfs rename filesystem|volume|snapshot
filesystem|volume|snapshot
zfs rename [-p] filesystem|volume filesystem|volume
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. Snapshots are the only dataset that can
be renamed recursively.
zfs list [-r|-d depth] [-H] [-o property[,...]] [ -t type[,...]] [ -s property ] ... [ -S property ] ...
[filesystem|volume|snapshot] ...
Lists the property information for the given datasets in tabular form. If specified, you can list
property information by the absolute pathname or the relative pathname. By default, all file systems
and volumes are displayed. Snapshots are displayed if the listsnaps property is on (the default is
off) . The following fields are 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 Properties" 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 -o name,avail,used,usedsnap,usedds,usedrefreserv,usedchild
-t filesystem,volume syntax.
-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 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 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, specifying -t snapshot displays only snapshots.
zfs set property=value filesystem|volume|snapshot ...
Sets the property to the given value for each dataset. Only some properties can be edited. See the
"Properties" section for more information on what properties can be set and acceptable values.
Numeric values can be specified as exact values, or in a human-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.
zfs get [-r|-d depth] [-Hp] [-o all | field[,...] [-s source[,...]] all | 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 except the RECEIVED column are displayed by default; specify particular or all columns,
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 that apply to the given dataset's type
(filesystem, volume, or snapshot).
-r
Recursively display properties for any children.
-d depth
Recursively display any children of the dataset, limiting the recursion to depth. A depth of 1
will display only the dataset and its direct children.
-H
Display output in a form more easily parsed by scripts. Any headers are omitted, and fields are
explicitly separated by a single tab instead of an arbitrary amount of space.
-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 [-v]
Displays a list of file systems that are not the most recent version.
zfs upgrade [-r] [-V version] [-a | filesystem]
Upgrades file systems to a new on-disk version. Once this is done, the file systems will no longer be
accessible on systems running older versions of the software. zfs send streams generated from new
snapshots of these file systems cannot be accessed on systems running older versions of the software.
In general, the file system version is independent of the pool version. 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 systems
-V version
Upgrade to the specified version. If the -V flag is not specified, this command upgrades to the
most recent version. This option can only be used to increase the version number, and only up to
the most recent version supported by this software.
zfs userspace [-niHp] [-o field[,...]] [-sS field]... [-t type [,...]] filesystem | snapshot
Displays space consumed by, and quotas on, each user in the specified filesystem or snapshot. This
corresponds to the userused@user and userquota@user properties.
-n
Print numeric ID instead of user/group name.
-H
Do not print headers, use tab-delimited output.
-p
Use exact (parseable) numeric output.
-o field[,...]
Display only the specified fields from the following set, type,name,used,quota.The default is to
display all fields.
-s field
Sort output by this field. The s and S flags may be specified multiple times to sort first by one
field, then by another. The default is -s type -s name.
-S field
Sort by this field in reverse order. See -s.
-t type[,...]
Print only the specified types from the following set, all,posixuser,smbuser,posixgroup,smbgroup.
The default is -t posixuser,smbuser
The default can be changed to include group types.
-i
Translate SID to POSIX ID. 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 specified filesystem or snapshot. This
subcommand is identical to zfs userspace, except that the default types to display are -t
posixgroup,smbgroup.
-
zfs mount
Displays all ZFS file systems currently mounted.
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 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.
-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 available ZFS file systems.
-a
Share all available ZFS file systems. Invoked automatically as part of the boot process.
filesystem
Share the specified filesystem according to the sharenfs and sharesmb properties. File systems
are shared when the sharenfs or sharesmb property is set.
zfs unshare -a | filesystem|mountpoint
Unshares currently shared ZFS file systems. This is invoked automatically as part of the shutdown
process.
-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 [-DvRp] [-[iI] 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.
-D
Perform dedup processing on the stream. Deduplicated streams cannot be received on systems that
do not support the stream deduplication feature.
-i snapshot
Generate 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
Generate a stream package that sends all intermediary snapshots from the first snapshot to the
second snapshot. For example, -I @a fs@d is similar to -i @a fs@b; -i @b fs@c; -i @c fs@d. The
incremental source snapshot may be specified as with the -i option.
-R
Generate a replication stream package, which will replicate the specified filesystem, and all
descendent file systems, up to the named snapshot. When received, all properties, 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 systems that do not exist on the sending side are destroyed.
-p
Send properties.
-v
Print verbose information about the stream package generated.
The format of the stream is committed. You will be able to receive your streams on future versions of
ZFS.
zfs receive [-vnFu] filesystem|volume|snapshot
zfs receive [-vnFu] [-d | -e] filesystem
Creates a snapshot whose contents are as specified in the stream 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.
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 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 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
Use 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
Use the last element of the sent snapshot path to determine the name of the new snapshot as
described in the paragraph above.
-u
File system that is associated with the received stream is not mounted.
-v
Print verbose information about the stream and the time required to perform the receive
operation.
-n
Do not actually receive the stream. This can be useful in conjunction with the -v option to
verify the name the receive operation would use.
-F
Force a rollback of the file system to the most recent snapshot 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.
zfs allow filesystem | volume
Displays permissions that have been delegated on the specified filesystem or volume. See the other
forms of zfs allow for more information.
zfs allow [-ldug] "everyone"|user|group[,...] perm|@setname[,...] filesystem| volume
zfs allow [-ld] -e perm|@setname[,...] filesystem | volume
Delegates ZFS administration permission for the file systems to non-privileged users.
[-ug] "everyone"|user|group[,...]
Specifies to whom the permissions are delegated. Multiple entities can be specified as a comma-
separated list. If 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." Multiple permissions may be specified
as a comma-separated list. Permission names are the same as ZFS subcommand and property names.
See the property list below. Property set names, which begin with an at sign (@) , may be
specified. See the -s form below for details.
[-ld] filesystem|volume
Specifies where the permissions are delegated. If neither of the -ld options are specified, or
both are, then the permissions are allowed for the file system or volume, and all of its
descendents. If only the -l option is used, then is allowed "locally" only for the specified file
system. If only the -d option is used, then is allowed only for the descendent file systems.
Permissions are generally the ability to use a ZFS subcommand or change a ZFS property. The following
permissions are available:
NAME TYPE NOTES
allow subcommand Must also have the permission that is
being allowed
clone subcommand Must also have the 'create' ability and
'mount'
ability in the origin file system
create subcommand Must also have the 'mount' ability
destroy subcommand Must also have the 'mount' ability
hold subcommand Allows adding a user hold to a snapshot
mount subcommand Allows mount/umount of ZFS datasets
promote subcommand Must also have the 'mount' and 'promote'
ability in the origin file system
receive subcommand Must also have the 'mount' and 'create'
ability
release subcommand Allows releasing a user hold which
might destroy the snapshot
rename subcommand Must also have the 'mount' and 'create'
ability in the new parent
rollback subcommand
send subcommand
share subcommand Allows sharing file systems over NFS or
SMB protocols
snapshot subcommand
groupquota other Allows accessing any groupquota@...
property
groupused other Allows reading any groupused@... property
userprop other Allows changing any user property
userquota other Allows accessing any userquota@...
property
userused other Allows reading any userused@... property
aclinherit property
aclmode property
atime property
canmount property
casesensitivity property
checksum property
compression property
copies property
dedup property
devices property
exec property
logbias property
mlslabel property
mountpoint property
nbmand property
normalization property
primarycache property
quota property
readonly property
recordsize property
refquota property
refreservation property
reservation property
secondarycache property
setuid property
shareiscsi property
sharenfs property
sharesmb property
snapdir property
utf8only property
version property
volblocksize property
volsize property
vscan property
xattr property
zoned property
zfs allow -c perm|@setname[,...] filesystem|volume
Sets "create time" permissions. These permissions are granted (locally) to the creator of any newly-
created descendent file system.
zfs allow -s @setname perm|@setname[,...] filesystem|volume
Defines or adds permissions to a permission set. The set can be used by other zfs allow commands for
the specified file system and its descendents. Sets are evaluated dynamically, so changes to a set
are immediately reflected. Permission sets follow the same naming restrictions as ZFS file systems,
but the name must begin with an "at sign" (@), and can be no more than 64 characters long.
zfs unallow [-rldug] "everyone"|user|group[,...] [perm|@setname[, ...]] filesystem|volume
zfs unallow [-rld] -e [perm|@setname [,...]] filesystem|volume
zfs unallow [-r] -c [perm|@setname[,...]]
filesystem|volume
Removes permissions that were granted with the zfs allow command. No permissions are explicitly
denied, so other permissions granted are still in effect. For example, if the permission is granted
by an ancestor. If no permissions are specified, then all permissions for the specified user, group,
or everyone are removed. Specifying "everyone" (or using the -e option) only removes the permissions
that were granted to "everyone", not all permissions for every user and group. See the zfs allow
command for a description of the -ldugec options.
-r
Recursively remove the permissions from this file system and all descendents.
zfs unallow [-r] -s @setname [perm|@setname[,...]]
filesystem|volume
Removes permissions from a permission set. If no permissions are specified, then all permissions are
removed, thus removing the set entirely.
zfs hold [-r] tag snapshot...
Adds a single reference, named with the tag argument, to the specified snapshot or snapshots. Each
snapshot has its own tag namespace, and tags must be unique within that space.
If a hold exists on a snapshot, attempts to destroy that snapshot by using the zfs destroy command
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 snapshots.
-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.
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 compression for pool/home/anne.
# zfs set compression=off pool/home
# zfs set compression=on pool/home/anne
Example 5 Listing ZFS Datasets
The following command lists all active file systems and volumes in the system. Snapshots are displayed if
the listsnaps property is on. The default is off. See zpool(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 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 Mon Nov 9 15:05 2009 -
pool/home/bob used 282M -
pool/home/bob available 134G -
pool/home/bob referenced 282M -
pool/home/bob compressratio 1.00x -
pool/home/bob mounted yes -
pool/home/bob quota none default
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 groupmask 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 4 -
pool/home/bob utf8only off -
pool/home/bob normalization none -
pool/home/bob casesensitivity sensitive -
pool/home/bob vscan off default
pool/home/bob nbmand off default
pool/home/bob sharesmb off default
pool/home/bob refquota none default
pool/home/bob refreservation none default
pool/home/bob primarycache all default
pool/home/bob secondarycache all default
pool/home/bob usedbysnapshots 0 -
pool/home/bob usedbydataset 282M -
pool/home/bob usedbychildren 0 -
pool/home/bob usedbyrefreservation 0 -
pool/home/bob logbias latency default
pool/home/bob dedup off default
pool/home/bob mlslabel none 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 20G
pool/home/bob compression on
Example 8 Rolling Back a ZFS File System
The following command reverts the contents of pool/home/anne to the snapshot named yesterday, deleting
all intermediate snapshots.
# zfs rollback -r pool/home/anne@yesterday
Example 9 Creating a ZFS Clone
The following command creates a writable file system whose initial 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@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 Creating a ZFS Volume as an 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 iscsitadm(1M).
Example 16 Performing a Rolling Snapshot
The following example shows how to maintain a history of snapshots with a consistent naming scheme. To
keep a week's worth of snapshots, the user destroys the oldest snapshot, renames the remaining snapshots,
and then creates a new snapshot, as follows:
# zfs destroy -r pool/users@7daysago
# zfs rename -r pool/users@6daysago @7daysago
# zfs rename -r pool/users@5daysago @6daysago
# zfs rename -r pool/users@yesterday @5daysago
# zfs rename -r pool/users@yesterday @4daysago
# zfs rename -r pool/users@yesterday @3daysago
# zfs rename -r pool/users@yesterday @2daysago
# zfs rename -r pool/users@today @yesterday
# zfs snapshot -r pool/users@today
Example 17 Setting sharenfs Property Options on a ZFS File System
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.
# # 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 qualified hostname.
Example 18 Delegating ZFS Administration Permissions on a ZFS Dataset
The following example shows how to set permissions so that user cindys can create, destroy, mount, and
take snapshots on tank/cindys. The permissions on tank/cindys are also displayed.
# zfs allow cindys create,destroy,mount,snapshot tank/cindys
# zfs allow tank/cindys
-------------------------------------------------------------
Local+Descendent permissions on (tank/cindys)
user cindys create,destroy,mount,snapshot
-------------------------------------------------------------
Because the tank/cindys mount point permission is set to 755 by default, user cindys will be unable to
mount file systems under tank/cindys. Set an ACL similar to the following syntax to provide mount point
access:
# chmod A+user:cindys:add_subdirectory:allow /tank/cindys
Example 19 Delegating Create Time Permissions on a ZFS Dataset
The following example shows how to grant anyone in the group staff to create file systems in tank/users.
This syntax also allows staff members to destroy their own file systems, but not destroy anyone else's
file system. The permissions on tank/users are also displayed.
# # zfs allow staff create,mount tank/users
# zfs allow -c destroy tank/users
# zfs allow tank/users
-------------------------------------------------------------
Create time permissions on (tank/users)
create,destroy
Local+Descendent permissions on (tank/users)
group staff create,mount
-------------------------------------------------------------
Example 20 Defining and Granting a Permission Set on a ZFS Dataset
The following example shows how to define and grant a permission set on the tank/users file system. The
permissions on tank/users are also displayed.
# zfs allow -s @pset create,destroy,snapshot,mount tank/users
# zfs allow staff @pset tank/users
# zfs allow tank/users
-------------------------------------------------------------
Permission sets on (tank/users)
@pset create,destroy,mount,snapshot
Create time permissions on (tank/users)
create,destroy
Local+Descendent permissions on (tank/users)
group staff @pset,create,mount
-------------------------------------------------------------
Example 21 Delegating Property Permissions on a ZFS Dataset
The following example shows to grant the ability to set quotas and reservations on the users/home file
system. The permissions on users/home are also displayed.
# zfs allow cindys quota,reservation users/home
# zfs allow users/home
-------------------------------------------------------------
Local+Descendent permissions on (users/home)
user cindys quota,reservation
-------------------------------------------------------------
cindys% zfs set quota=10G users/home/marks
cindys% zfs get quota users/home/marks
NAME PROPERTY VALUE SOURCE
users/home/marks quota 10G local
Example 22 Removing ZFS Delegated Permissions on a ZFS Dataset
The following example shows how to remove the snapshot permission from the staff group on the tank/users
file system. The permissions on tank/users are also displayed.
# zfs unallow staff snapshot tank/users
# zfs allow tank/users
-------------------------------------------------------------
Permission sets on (tank/users)
@pset create,destroy,mount,snapshot
Create time permissions on (tank/users)
create,destroy
Local+Descendent permissions on (tank/users)
group staff @pset,create,mount
-------------------------------------------------------------
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:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Availability │SUNWzfsu │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │Committed │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSO
ssh(1), iscsitadm(1M), mount(1M), share(1M), sharemgr(1M), unshare(1M), zonecfg(1M), zpool(1M), chmod(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 collection.
For information about using the ZFS web-based management tool and other ZFS features, see the Solaris ZFS
Administration Guide.