zfs —
configure ZFS datasets
zfs |
subcommand
[arguments ] |
The
zfs command configures ZFS datasets
within a ZFS storage pool, as described in
zpool(8). A dataset is identified by a unique
path within the ZFS namespace. For example:
pool/{filesystem,volume,snapshot}
where the maximum length of a dataset name is
MAXNAMELEN (256B) and the maximum amount of
nesting allowed in a path is 50 levels deep.
A dataset can be one of the following:
- file system
- 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 non-standard
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 when a block device is required. 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.
- bookmark
- Much like a snapshot, but without the hold on
on-disk data. It can be used as the source of a send (but not for a
receive). It is specified as
filesystem#name
or
volume#name.
See
zfsconcepts(7) for details.
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 properties, see
zfsprops(7).
Enabling the
encryption feature allows for the
creation of encrypted filesystems and volumes. ZFS will encrypt file and zvol
data, file attributes, ACLs, permission bits, directory listings, FUID
mappings, and
userused/
groupused/
projectused
data. For an overview of encryption, see
zfs-load-key(8).
All subcommands that modify state are logged persistently to the pool in their
original form.
zfs
-?- Displays a help message.
zfs
-V,
--version-
zfs
version- Displays the software version of the
zfs userland utility and the zfs kernel
module.
- zfs-list(8)
- Lists the property information for the given datasets in tabular
form.
- zfs-create(8)
- Creates a new ZFS file system or volume.
- zfs-destroy(8)
- Destroys the given dataset(s), snapshot(s), or bookmark.
- zfs-rename(8)
- Renames the given dataset (filesystem or snapshot).
- zfs-upgrade(8)
- Manage upgrading the on-disk version of filesystems.
- zfs-snapshot(8)
- Creates snapshots with the given names.
- zfs-rollback(8)
- Roll back the given dataset to a previous snapshot.
- zfs-hold(8)/zfs-release(8)
- Add or remove a hold reference to the specified snapshot or snapshots. If
a hold exists on a snapshot, attempts to destroy that snapshot by using
the
zfs
destroy command return
EBUSY.
- zfs-diff(8)
- Display the difference between a snapshot of a given filesystem and
another snapshot of that filesystem from a later time or the current
contents of the filesystem.
- zfs-clone(8)
- Creates a clone of the given snapshot.
- zfs-promote(8)
- Promotes a clone file system to no longer be dependent on its
“origin” snapshot.
- zfs-send(8)
- Generate a send stream, which may be of a filesystem, and may be
incremental from a bookmark.
- zfs-receive(8)
- 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(8) subcommand, which by default
creates a full stream.
- zfs-bookmark(8)
- Creates a new bookmark of the given snapshot or bookmark. Bookmarks mark
the point in time when the snapshot was created, and can be used as the
incremental source for a
zfs
send command.
- zfs-redact(8)
- Generate a new redaction bookmark. This feature can be used to allow
clones of a filesystem to be made available on a remote system, in the
case where their parent need not (or needs to not) be usable.
- zfs-get(8)
- Displays properties for the given datasets.
- zfs-set(8)
- Sets the property or list of properties to the given value(s) for each
dataset.
- zfs-inherit(8)
- Clears the specified property, causing it to be inherited from an
ancestor, restored to default if no ancestor has the property set, or with
the
-S option reverted to the received
value if one exists.
- zfs-userspace(8)/zfs-groupspace(8)/zfs-projectspace(8)
- Displays space consumed by, and quotas on, each user, group, or project in
the specified filesystem or snapshot.
- zfs-project(8)
- List, set, or clear project ID and/or inherit flag on the file(s) or
directories.
- zfs-mount(8)
- Displays all ZFS file systems currently mounted, or mount ZFS filesystem
on a path described by its mountpoint
property.
- zfs-unmount(8)
- Unmounts currently mounted ZFS file systems.
- zfs-share(8)
- Shares available ZFS file systems.
- zfs-unshare(8)
- Unshares currently shared ZFS file systems.
- zfs-allow(8)
- Delegate permissions on the specified filesystem or volume.
- zfs-unallow(8)
- Remove delegated permissions on the specified filesystem or volume.
- zfs-change-key(8)
- Add or change an encryption key on the specified dataset.
- zfs-load-key(8)
- Load the key for the specified encrypted dataset, enabling access.
- zfs-unload-key(8)
- Unload a key for the specified dataset, removing the ability to access the
dataset.
- zfs-program(8)
- Execute ZFS administrative operations programmatically via a Lua
script-language channel program.
- zfs-jail(8)
- Attaches a filesystem to a jail.
- zfs-unjail(8)
- Detaches a filesystem from a jail.
- zfs-wait(8)
- Wait for background activity in a filesystem to complete.
The
zfs utility exits
0 on success,
1 if
an error occurs, and
2 if invalid command line
options were specified.
- 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
listsnaps=on.
The default is off. See
zpoolprops(7) 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 Tue Jul 21 15:53 2009 -
pool/home/bob used 21K -
pool/home/bob available 20.0G -
pool/home/bob referenced 21K -
pool/home/bob compressratio 1.00x -
pool/home/bob mounted yes -
pool/home/bob quota 20G local
pool/home/bob reservation none default
pool/home/bob recordsize 128K default
pool/home/bob mountpoint /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 acltype off default
pool/home/bob aclmode discard default
pool/home/bob aclinherit restricted default
pool/home/bob canmount on default
pool/home/bob xattr on default
pool/home/bob copies 1 default
pool/home/bob version 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 21K -
pool/home/bob usedbychildren 0 -
pool/home/bob usedbyrefreservation 0 -
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@a and
poolB/received/fs@b, respectively.
poolB must contain the file system
poolB/received, and must not initially
contain poolB/received/fs.
# zfs send pool/fs@a |
ssh host zfs receive poolB/received/fs@a
# zfs send -i a pool/fs@b |
ssh host zfs receive poolB/received/fs
- Example 13: Using the
zfs
receive
-d Option
- The following command sends a full stream of
poolA/fsA/fsB@snap to a remote machine,
receiving it into
poolB/received/fsA/fsB@snap. The
fsA/fsB@snap portion of the received
snapshot's name is determined from the name of the sent snapshot.
poolB must contain the file system
poolB/received. If
poolB/received/fsA does not exist, it is
created as an empty file system.
# zfs send poolA/fsA/fsB@snap |
ssh host zfs receive -d poolB/received
- Example 14: Setting User
Properties
- The following example sets the user-defined
com.example:department
property for a dataset:
#
zfs
set
com.example:department=12345
tank/accounting
- Example 15: Performing a
Rolling Snapshot
- The following example shows how to maintain a history of snapshots with a
consistent naming scheme. To keep a week's worth of snapshots, the user
destroys the oldest snapshot, renames the remaining snapshots, and then
creates a new snapshot, as follows:
# zfs destroy -r pool/users@7daysago
# zfs rename -r pool/users@6daysago @7daysago
# zfs rename -r pool/users@5daysago @6daysago
# zfs rename -r pool/users@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 commands show how to set
sharenfs property options to enable
read-write 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 17: Delegating ZFS
Administration Permissions on a ZFS Dataset
- The following example shows how to set permissions so that user
cindys can create, destroy, mount, and
take snapshots on tank/cindys. The
permissions on tank/cindys are also
displayed.
# zfs allow cindys create,destroy,mount,snapshot tank/cindys
# zfs allow tank/cindys
---- Permissions on tank/cindys --------------------------------------
Local+Descendent permissions:
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. Add an ACE
similar to the following syntax to provide mount point access:
#
chmod
A+user:cindys:add_subdirectory:allow
/tank/cindys
- Example 18: Delegating
Create Time Permissions on a ZFS Dataset
- The following example shows how to grant anyone in the group
staff to create file systems in
tank/users. This syntax also allows staff
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
---- Permissions on tank/users ---------------------------------------
Permission sets:
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 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
---- Permissions on tank/users ---------------------------------------
Permission sets:
@pset create,destroy,mount,snapshot
Local+Descendent permissions:
group staff @pset
- Example 20: Delegating
Property Permissions on a ZFS Dataset
- The following example shows to grant the ability to set quotas and
reservations on the users/home file
system. The permissions on users/home are
also displayed.
# zfs allow cindys quota,reservation users/home
# zfs allow users/home
---- Permissions on users/home ---------------------------------------
Local+Descendent permissions:
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 21: Removing ZFS
Delegated Permissions on a ZFS Dataset
- The following example shows how to remove the snapshot permission from the
staff group on the
tank/users file system. The permissions on
tank/users are also displayed.
# zfs unallow staff snapshot tank/users
# zfs allow tank/users
---- Permissions on tank/users ---------------------------------------
Permission sets:
@pset create,destroy,mount,snapshot
Local+Descendent permissions:
group staff @pset
- Example 22: Showing the
differences between a snapshot and a ZFS Dataset
- The following example shows how to see what has changed between a prior
snapshot of a ZFS dataset and its current state. The
-F option is used to indicate type
information for the files affected.
# zfs diff -F tank/test@before tank/test
M / /tank/test/
M F /tank/test/linked (+1)
R F /tank/test/oldname -> /tank/test/newname
- F /tank/test/deleted
+ F /tank/test/created
M F /tank/test/modified
- Example 23: Creating a
bookmark
- The following example create a bookmark to a snapshot. This bookmark can
then be used instead of snapshot in send streams.
#
zfs
bookmark
rpool@snapshot
rpool#bookmark
- Example 24: Setting
sharesmb Property Options on a
ZFS File System
- The following example show how to share SMB filesystem through ZFS. Note
that a user and their password must be given.
#
smbmount
//127.0.0.1/share_tmp /mnt/tmp
-o
user=workgroup/turbo,password=obrut,uid=1000
Minimal /etc/samba/smb.conf configuration
is required, as follows.
Samba will need to bind to the loopback interface for the ZFS utilities to
communicate with Samba. This is the default behavior for most Linux
distributions.
Samba must be able to authenticate a user. This can be done in a number of
ways (passwd(5), LDAP,
smbpasswd(5), &c.). How to do this is
outside the scope of this document – refer to
smb.conf(5) for more information.
See the USERSHARES section
for all configuration options, in case you need to modify any options of
the share afterwards. Do note that any changes done with the
net(8) command will be undone if the share is
ever unshared (like via a reboot).
- ZFS_MOUNT_HELPER
- Cause
zfs
mount to use
mount(8) to mount ZFS datasets. This option
is provided for backwards compatibility with older ZFS versions.
Committed.
attr(1),
gzip(1),
ssh(1),
chmod(2),
fsync(2),
stat(2),
write(2),
acl(5),
attributes(5),
exports(5),
zfsconcepts(7),
zfsprops(7),
exportfs(8),
mount(8),
net(8),
selinux(8),
zfs-allow(8),
zfs-bookmark(8),
zfs-change-key(8),
zfs-clone(8),
zfs-create(8),
zfs-destroy(8),
zfs-diff(8),
zfs-get(8),
zfs-groupspace(8),
zfs-hold(8),
zfs-inherit(8),
zfs-jail(8),
zfs-list(8),
zfs-load-key(8),
zfs-mount(8),
zfs-program(8),
zfs-project(8),
zfs-projectspace(8),
zfs-promote(8),
zfs-receive(8),
zfs-redact(8),
zfs-release(8),
zfs-rename(8),
zfs-rollback(8),
zfs-send(8),
zfs-set(8),
zfs-share(8),
zfs-snapshot(8),
zfs-unallow(8),
zfs-unjail(8),
zfs-unload-key(8),
zfs-unmount(8),
zfs-unshare(8),
zfs-upgrade(8),
zfs-userspace(8),
zfs-wait(8),
zpool(8)