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:
pool[
/component
]
/component
for example:
rpool/var/log
The maximum length of a dataset name is
ZFS_MAX_DATASET_NAME_LEN -
1 ASCII characters (currently 255) satisfying
[A-Za-z_.:/ -]. Additionally snapshots are
allowed to contain a single
@ character, while
bookmarks are allowed to contain a single
#
character.
/ is used as separator between
components. The maximum amount of nesting allowed in a path is
zfs_max_dataset_nesting levels deep. ZFS tunables
(
zfs_*) are explained in
zfs(4).
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 files 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:[::1],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 creates a bookmark to a snapshot. This bookmark can then
be used instead of a 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.
- ZFS_SET_PIPE_MAX
- Tells
zfs to set the maximum pipe size
for sends/recieves. Disabled by default on Linux due to an unfixed
deadlock in Linux's pipe size handling code.
- ZFS_MODULE_TIMEOUT
- Time, in seconds, to wait for /dev/zfs
to appear. Defaults to 10, max
600 (10 minutes). If
<0, wait forever; if
0, don't wait.
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)