NAME
zfs - configures ZFS file systems
SYNOPSIS
zfs [-?]
zfs create [[-o property=value]]... filesystem
zfs create [-s] [-b blocksize] [[-o property=value]]... -V size volume
zfs destroy [-rRf] filesystem|volume|snapshot
zfs clone snapshot filesystem|volume
zfs promote filesystem
zfs rename filesystem|volume|snapshot
[ filesystem|volume|snapshot]
zfs snapshot [-r] filesystem@name|volume@name
zfs rollback [-rRf] snapshot
zfs list [-rH] [-o prop[,prop] ]... [ -t type[,type]...]
[ -s prop [-s prop]... [ -S prop [-S prop]...
[ filesystem|volume|snapshot|/pathname|./pathname ...
zfs set property=value filesystem|volume ...
zfs get [-rHp] [-o field[,field]...]
[ -s source[,source]...] all | property[,property]...
filesystem|volume|snapshot ...
zfs inherit [-r] property filesystem|volume... ...
zfs mount
zfs mount [-o options] [-O] -a
zfs mount [-o options] [-O] filesystem
zfs unmount [-f] -a
zfs unmount [-f] filesystem|mountpoint
zfs share -a
zfs share filesystem
zfs unshare [-f] -a
zfs unshare [-f] filesystem|mountpoint
zfs send [-i snapshot1] snapshot2
zfs receive [-vnF ] filesystem|volume|snapshot
zfs receive [-vnF ] -d filesystem
zfs jail jailid filesystem
zfs unjail jailid filesystem
DESCRIPTION
The
zfs command configures
ZFS datasets within a
ZFS
storage pool, as described in
zpool(1M). A dataset is identified by a
unique path within the
ZFS namespace. For example:
pool/{filesystem,volume,snapshot}
where the maximum length of a dataset name is
MAXNAMELEN (256 bytes).
A dataset can be one of the following:
file system
A standard POSIX file system.
ZFS file systems can be mounted within the standard file system
namespace and behave like any other file system.
volume
A logical volume exported as a raw or block
device. This type of dataset should only be used under special circumstances.
File systems are typically used in most environments. Volumes cannot be used
in a non-global zone.
snapshot
A read-only version of a file system or
volume at a given point in time. It is specified as filesystem@name or
volume@name.
ZFS File System Hierarchy
A
ZFS storage pool is a logical collection of devices that provide space
for datasets. A storage pool is also the root of the
ZFS file system
hierarchy.
The root of the pool can be accessed as a file system, such as mounting and
unmounting, taking snapshots, and setting properties. The physical storage
characteristics, however, are managed by the
zpool(1M) command.
See
zpool(1M) for more information on creating and administering pools.
Snapshots
A snapshot is a read-only copy of a file system or volume. Snapshots can be
created extremely quickly, and initially consume no additional space within
the pool. As data within the active dataset changes, the snapshot consumes
more data than would otherwise be shared with the active dataset.
Snapshots can have arbitrary names. Snapshots of volumes can be cloned or rolled
back, but cannot be accessed independently.
File system snapshots can be accessed under the ".zfs/snapshot"
directory in the root of the file system. Snapshots are automatically mounted
on demand and may be unmounted at regular intervals. The visibility of the
".zfs" directory can be controlled by the "snapdir"
property.
Clones
A clone is a writable volume or file system whose initial contents are the same
as another dataset. As with snapshots, creating a clone is nearly
instantaneous, and initially consumes no additional space.
Clones can only be created from a snapshot. When a snapshot is cloned, it
creates an implicit dependency between the parent and child. Even though the
clone is created somewhere else in the dataset hierarchy, the original
snapshot cannot be destroyed as long as a clone exists. The "origin"
property exposes this dependency, and the
destroy command lists any
such dependencies, if they exist.
The clone parent-child dependency relationship can be reversed by using the
"
promote" subcommand. This causes the "origin"
file system to become a clone of the specified file system, which makes it
possible to destroy the file system that the clone was created from.
Mount Points
Creating a
ZFS file system is a simple operation, so the number of file
systems per system will likely be numerous. To cope with this,
ZFS
automatically manages mounting and unmounting file systems without the need to
edit the
/etc/vfstab file. All automatically managed file systems are
mounted by
ZFS at boot time.
By default, file systems are mounted under
/path, where
path is the name of the file system in the
ZFS namespace.
Directories are created and destroyed as needed.
A file system can also have a mount point set in the "mountpoint"
property. This directory is created as needed, and
ZFS automatically
mounts the file system when the "
zfs mount -a" command is
invoked (without editing
/etc/vfstab). The mountpoint property can be
inherited, so if
pool/home has a mount point of
/export/stuff,
then
pool/home/user automatically inherits a mount point of
/export/stuff/user.
A file system mountpoint property of "none" prevents the file system
from being mounted.
If needed,
ZFS file systems can also be managed with traditional tools
(
mount,
umount,
/etc/vfstab). If a file system's mount
point is set to "legacy",
ZFS makes no attempt to manage the
file system, and the administrator is responsible for mounting and unmounting
the file system.
Zones
A
ZFS file system can be added to a non-global zone by using zonecfg's
"
add fs" subcommand. A
ZFS file system that is added
to a non-global zone must have its mountpoint property set to legacy.
The physical properties of an added file system are controlled by the global
administrator. However, the zone administrator can create, modify, or destroy
files within the added file system, depending on how the file system is
mounted.
A dataset can also be delegated to a non-global zone by using zonecfg's "
add dataset" subcommand. You cannot delegate a dataset to one zone
and the children of the same dataset to another zone. The zone administrator
can change properties of the dataset or any of its children. However, the
"quota" property is controlled by the global administrator.
A
ZFS volume can be added as a device to a non-global zone by using
zonecfg's "
add device" subcommand. However, its physical
properties can only be modified by the global administrator.
For more information about
zonecfg syntax, see
zonecfg(1M).
After a dataset is delegated to a non-global zone, the "zoned"
property is automatically set. A zoned file system cannot be mounted in the
global zone, since the zone administrator might have to set the mount point to
an unacceptable value.
The global administrator can forcibly clear the "zoned" property,
though this should be done with extreme care. The global administrator should
verify that all the mount points are acceptable before clearing the property.
Native Properties
Properties are divided into two types, native properties and user defined
properties. Native properties either export internal statistics or control
ZFS behavior. In addition, native properties are either editable or
read-only. User properties have no effect on
ZFS behavior, but you can
use them to annotate datasets in a way that is meaningful in your environment.
For more information about user properties, see the "User
Properties" section.
Every dataset has a set of properties that export statistics about the dataset
as well as control various behavior. Properties are inherited from the parent
unless overridden by the child. Snapshot properties can not be edited; they
always inherit their inheritable properties. Properties that are not
applicable to snapshots are not displayed.
The values of numeric properties can be specified using the following
human-readable suffixes (for example, "k", "KB",
"M", "Gb", etc, up to Z for zettabyte). The following are
all valid (and equal) specifications:
"1536M", "1.5g", "1.50GB".
The values of non-numeric properties are case sensitive and must be lowercase,
except for "mountpoint" and "sharenfs".
The first set of properties consist of read-only statistics about the dataset.
These properties cannot be set, nor are they inherited. Native properties
apply to all dataset types unless otherwise noted.
type
The type of dataset: "filesystem",
"volume", "snapshot", or "clone".
creation
The time this dataset was created.
used
The amount of space consumed by this dataset
and all its descendants. This is the value that is checked against this
dataset's quota and reservation. The space used does not include this
dataset's reservation, but does take into account the reservations of any
descendant datasets. The amount of space that a dataset consumes from its
parent, as well as the amount of space that will be freed if this dataset is
recursively destroyed, is the greater of its space used and its reservation.
When snapshots (see the "Snapshots" section) are created, their space
is initially shared between the snapshot and the file system, and possibly
with previous snapshots. As the file system changes, space that was previously
shared becomes unique to the snapshot, and counted in the snapshot's space
used. Additionally, deleting snapshots can increase the amount of space unique
to (and used by) other snapshots.
The amount of space used, available, or referenced does not take into account
pending changes. Pending changes are generally accounted for within a few
seconds. Committing a change to a disk using
fsync(3c) or
O_SYNC
does not necessarily guarantee that the space usage information is updated
immediately.
available
The amount of space available to the dataset
and all its children, assuming that there is no other activity in the pool.
Because space is shared within a pool, availability can be limited by any
number of factors, including physical pool size, quotas, reservations, or
other datasets within the pool.
This property can also be referred to by its shortened column name,
"avail".
referenced
The amount of data that is accessible by this
dataset, which may or may not be shared with other datasets in the pool. When
a snapshot or clone is created, it initially references the same amount of
space as the file system or snapshot it was created from, since its contents
are identical.
This property can also be referred to by its shortened column name,
"refer".
compressratio
The compression ratio achieved for this
dataset, expressed as a multiplier. Compression can be turned on by running
"zfs set compression=on dataset". The default value is
"off".
mounted
For file systems, indicates whether the file
system is currently mounted. This property can be either "yes" or
"no".
origin
For cloned file systems or volumes, the
snapshot from which the clone was created. The origin cannot be destroyed
(even with the -r or -f options) so long as a clone
exists.
The following two properties can be set to control the way space is allocated
between datasets. These properties are not inherited, but do affect their
descendants.
quota=size |
none
Limits the amount of space a dataset and its
descendants can consume. This property enforces a hard limit on the amount of
space used. This includes all space consumed by descendants, including file
systems and snapshots. Setting a quota on a descendant of a dataset that
already has a quota does not override the ancestor's quota, but rather imposes
an additional limit.
Quotas cannot be set on volumes, as the "volsize" property acts as an
implicit quota.
reservation=size |
none
The minimum amount of space guaranteed to a
dataset and its descendants. When the amount of space used is below this
value, the dataset is treated as if it were taking up the amount of space
specified by its reservation. Reservations are accounted for in the parent
datasets' space used, and count against the parent datasets' quotas and
reservations.
This property can also be referred to by its shortened column name,
"reserv".
volsize=size
For volumes, specifies the logical size of the
volume. By default, creating a volume establishes a reservation of equal size.
Any changes to
volsize are reflected in an equivalent change to the
reservation. The
volsize can only be set to a multiple of
volblocksize, and cannot be zero.
The reservation is kept equal to the volume's logical size to prevent unexpected
behavior for consumers. Without the reservation, the volume could run out of
space, resulting in undefined behavior or data corruption, depending on how
the volume is used. These effects can also occur when the volume size is
changed while it is in use (particularly when shrinking the size). Extreme
care should be used when adjusting the volume size.
Though not recommended, a "sparse volume" (also known as "thin
provisioning") can be created by specifying the
-s option to the
"
zfs create -V" command, or by changing the reservation
after the volume has been created. A "sparse volume" is a volume
where the reservation is less then the volume size. Consequently, writes to a
sparse volume can fail with
ENOSPC when the pool is low on space. For a
sparse volume, changes to
volsize are not reflected in the
reservation.
volblocksize=blocksize
For volumes, specifies the block size of the
volume. The
blocksize cannot be changed once the volume has been
written, so it should be set at volume creation time. The default
blocksize for volumes is 8 Kbytes. Any power of 2 from 512 bytes to 128
Kbytes is valid.
This property can also be referred to by its shortened column name,
"volblock".
recordsize=size
Specifies a suggested block size for files in
the file system. This property is designed solely for use with database
workloads that access files in fixed-size records.
ZFS automatically
tunes block sizes according to internal algorithms optimized for typical
access patterns.
For databases that create very large files but access them in small random
chunks, these algorithms may be suboptimal. Specifying a
"recordsize" greater than or equal to the record size of the
database can result in significant performance gains. Use of this property for
general purpose file systems is strongly discouraged, and may adversely affect
performance.
The size specified must be a power of two greater than or equal to 512 and less
than or equal to 128 Kbytes.
Changing the file system's
recordsize only affects files created
afterward; existing files are unaffected.
This property can also be referred to by its shortened column name,
"recsize".
mountpoint=path |
none |
legacy
Controls the mount point used for this file
system. See the "Mount Points" section for more information on how
this property is used.
When the mountpoint property is changed for a file system, the file system and
any children that inherit the mount point are unmounted. If the new value is
"legacy", then they remain unmounted. Otherwise, they are
automatically remounted in the new location if the property was previously
"legacy" or "none", or if they were mounted before the
property was changed. In addition, any shared file systems are unshared and
shared in the new location.
sharenfs=on |
off |
opts
Controls whether the file system is shared via
NFS, and what options are used. A file system with a sharenfs property
of "off" is managed through traditional tools such as
share(1M),
unshare(1M), and
dfstab(4). Otherwise, the
file system is automatically shared and unshared with the "
zfs
share" and "
zfs unshare" commands. If the property
is set to "on", the
share(1M) command is invoked with no
options. Otherwise, the
share(1M) command is invoked with options
equivalent to the contents of this property.
When the "sharenfs" property is changed for a dataset, the dataset and
any children inheriting the property are re-shared with the new options, only
if the property was previously "off", or if they were shared before
the property was changed. If the new property is "off", the file
systems are unshared.
shareiscsi=on |
off
Like the "sharenfs" property,
"shareiscsi" indicates whether a
ZFS volume is exported as an
iSCSI target. The acceptable values for this property are
"on", "off", and "type=disk". The default value
is "off". In the future, other target types might be supported. For
example, "tape".
You might want to set "shareiscsi=on" for a file system so that all
ZFS volumes within the file system are shared by default. Setting this
property on a file system has no direct effect, however.
checksum=on |
off |
fletcher2, |
fletcher4 |
sha256
Controls the checksum used to verify data
integrity. The default value is "on", which automatically selects an
appropriate algorithm (currently, fletcher2, but this may change in
future releases). The value "off" disables integrity checking on
user data. Disabling checksums is NOT a recommended practice.
compression=on |
off |
lzjb |
gzip |
gzip-N
Controls the compression algorithm used for
this dataset. The "lzjb" compression algorithm is optimized for
performance while providing decent data compression. Setting compression to
"on" uses the "lzjb" compression algorithm. The
"gzip" compression algorithm uses the same compression as the
gzip(1) command. You can specify the "gzip" level by using
the value "gzip-
N", where
N is an integer from 1
(fastest) to 9 (best compression ratio). Currently, "gzip" is
equivalent to "gzip-6" (which is also the default for
gzip(1)).
This property can also be referred to by its shortened column name
"compress".
atime=on |
off
Controls whether the access time for files is
updated when they are read. Turning this property off avoids producing write
traffic when reading files and can result in significant performance gains,
though it might confuse mailers and other similar utilities. The default value
is "on".
devices=on |
off
Controls whether device nodes can be opened on
this file system. The default value is "on".
exec=on |
off
Controls whether processes can be executed
from within this file system. The default value is "on".
setuid=on |
off
Controls whether the set-UID bit is
respected for the file system. The default value is "on".
readonly=on |
off
Controls whether this dataset can be modified.
The default value is "off".
This property can also be referred to by its shortened column name,
"rdonly".
zoned=on |
off
Controls whether the dataset is managed from a
non-global zone. See the "Zones" section for more information. The
default value is "off".
snapdir=hidden |
visible
Controls whether the ".zfs"
directory is hidden or visible in the root of the file system as discussed in
the "Snapshots" section. The default value is
"hidden".
aclmode=discard |
groupmask |
passthrough
Controls how an ACL is modified during
chmod(2). A file system with an "aclmode" property of
"discard" deletes all ACL entries that do not
represent the mode of the file. An "aclmode" property of "
groupmask" (the default) reduces user or group permissions. The
permissions are reduced, such that they are no greater than the group
permission bits, unless it is a user entry that has the same UID as the
owner of the file or directory. In this case, the ACL permissions are
reduced so that they are no greater than owner permission bits. A file system
with an "aclmode" property of " passthrough"
indicates that no changes will be made to the ACL other than generating
the necessary ACL entries to represent the new mode of the file or
directory.
aclinherit=discard |
noallow |
secure |
passthrough
Controls how ACL entries are inherited
when files and directories are created. A file system with an
"aclinherit" property of " discard" does not
inherit any ACL entries. A file system with an "aclinherit"
property value of " noallow" only inherits inheritable
ACL entries that specify "deny" permissions. The property
value " secure" (the default) removes the
"write_acl" and " write_owner" permissions
when the ACL entry is inherited. A file system with an
"aclinherit" property value of " passthrough"
inherits all inheritable ACL entries without any modifications made to
the ACL entries when they are inherited.
canmount=on |
off
If this property is set to
"
off", the file system cannot be mounted, and is ignored by
"
zfs mount -a". This is similar to setting the
"mountpoint" property to "
none", except that the
dataset still has a normal "mountpoint" property which can be
inherited. This allows datasets to be used solely as a mechanism to inherit
properties. One use case is to have two logically separate datasets have the
same mountpoint, so that the children of both datasets appear in the same
directory, but may have different inherited characteristics. The default value
is "
on".
This property is not inherited.
xattr=on |
off
Controls whether extended attributes are
enabled for this file system. The default value is "
on".
copies=1 |
2 |
3
Controls the number of copies of data stored
for this dataset. These copies are in addition to any redundancy provided by
the pool, for example, mirroring or raid-z. The copies are stored on different
disks, if possible. The space used by multiple copies is charged to the
associated file and dataset, changing the "used" property and
counting against quotas and reservations.
Changing this property only affects newly-written data. Therefore, set this
property at file system creation time by using the "
-o
copies=" option.
jailed=on |
off
Controls whether the dataset is managed from
within a jail. The default value is "off".
iscsioptions
This read-only property, which is hidden, is used by the
iSCSI target
daemon to store persistent information, such as the
IQN. It cannot be
viewed or modified using the
zfs command. The contents are not intended
for external consumers.
Temporary Mount Point Properties
When a file system is mounted, either through
mount(1M) for legacy mounts
or the "
zfs mount" command for normal file systems, its
mount options are set according to its properties. The correlation between
properties and mount options is as follows:
PROPERTY MOUNT OPTION
devices devices/nodevices
exec exec/noexec
readonly ro/rw
setuid setuid/nosetuid
xattr xattr/noxattr
In addition, these options can be set on a per-mount basis using the
-o
option, without affecting the property that is stored on disk. The values
specified on the command line override the values stored in the dataset. The
-nosuid option is an alias for "nodevices,nosetuid". These
properties are reported as "temporary" by the "
zfs
get" command. If the properties are changed while the dataset is
mounted, the new setting overrides any temporary settings.
User Properties
In addition to the standard native properties,
ZFS supports arbitrary
user properties. User properties have no effect on
ZFS behavior, but
applications or administrators can use them to annotate datasets.
User property names must contain a colon (":") character, to
distinguish them from native properties. They might contain lowercase letters,
numbers, and the following punctuation characters: colon (":"), dash
("-"), period ("."), and underscore ("_"). The
expected convention is that the property name is divided into two portions
such as "
module:
property", but this namespace is not
enforced by
ZFS. User property names can be at most 256 characters, and
cannot begin with a dash ("-").
When making programmatic use of user properties, it is strongly suggested to use
a reversed
DNS domain name for the
module component of property
names to reduce the chance that two independently-developed packages use the
same property name for different purposes. Property names beginning with
"com.sun." are reserved for use by Sun Microsystems.
The values of user properties are arbitrary strings, are always inherited, and
are never validated. All of the commands that operate on properties ("zfs
list", "zfs get", "zfs set", etc.) can be used to
manipulate both native properties and user properties. Use the "
zfs
inherit" command to clear a user property . If the property is not
defined in any parent dataset, it is removed entirely. Property values are
limited to 1024 characters.
Volumes as Swap or Dump Devices
To set up a swap area, create a
ZFS volume of a specific size and then
enable swap on that device. For more information, see the EXAMPLES section.
Do not swap to a file on a
ZFS file system. A
ZFS swap file
configuration is not supported.
Using a
ZFS volume as a dump device is not supported.
SUBCOMMANDS
All subcommands that modify state are logged persistently to the pool in their
original form.
zfs ?
Displays a help message.
zfs create [[
-o property=value]...]
filesystem
Creates a new
ZFS file system. The file
system is automatically mounted according to the "mountpoint"
property inherited from the parent.
-o property=value
Sets the specified property as if
"zfs set property=value" was invoked at the same time the
dataset was created. Any editable ZFS property can also be set at
creation time. Multiple -o options can be specified. An error results
if the same property is specified in multiple -o options.
zfs create [
-s] [
-b blocksize] [[
-o
property=value]...]
-V size volume
Creates a volume of the given size. The volume
is exported as a block device in
/dev/zvol/{dsk,rdsk}/path,
where
path is the name of the volume in the
ZFS namespace. The
size represents the logical size as exported by the device. By default, a
reservation of equal size is created.
size is automatically rounded up to the nearest 128 Kbytes to ensure that
the volume has an integral number of blocks regardless of
blocksize.
-s
Creates a sparse volume with no reservation.
See "volsize" in the Native Properties section for more information
about sparse volumes.
-o property=value
Sets the specified property as if
"zfs set property=value" was invoked at the same time the
dataset was created. Any editable ZFS property can also be set at
creation time. Multiple -o options can be specified. An error results
if the same property is specified in multiple -o options.
-b blocksize
Equivalent to "-o
volblocksize= blocksize". If this option is specified in
conjunction with " -o volblocksize", the
resulting behavior is undefined.
zfs destroy [
-rRf]
filesystem|
volume|
snapshot
Destroys the given dataset. By default, the
command unshares any file systems that are currently shared, unmounts any file
systems that are currently mounted, and refuses to destroy a dataset that has
active dependents (children, snapshots, clones).
-r
Recursively destroy all children. If a
snapshot is specified, destroy all snapshots with this name in descendant file
systems.
-R
Recursively destroy all dependents, including
cloned file systems outside the target hierarchy. If a snapshot is specified,
destroy all snapshots with this name in descendant file systems.
-f
Force an unmount of any file systems using the
" unmount -f" command. This option has no effect on non-file
systems or unmounted file systems.
Extreme care should be taken when applying either the
-r or the
-f
options, as they can destroy large portions of a pool and cause unexpected
behavior for mounted file systems in use.
zfs clone snapshot filesystem|
volume
Creates a clone of the given snapshot. See the
"Clones" section for details. The target dataset can be located
anywhere in the ZFS hierarchy, and is created as the same type as the
original.
zfs promote filesystem
Promotes a clone file system to no longer be
dependent on its "origin" snapshot. This makes it possible to
destroy the file system that the clone was created from. The clone
parent-child dependency relationship is reversed, so that the
"origin" file system becomes a clone of the specified file system.
The snaphot that was cloned, and any snapshots previous to this snapshot, are
now owned by the promoted clone. The space they use moves from the
"origin" file system to the promoted clone, so enough space must be
available to accommodate these snapshots. No new space is consumed by this
operation, but the space accounting is adjusted. The promoted clone must not
have any conflicting snapshot names of its own. The "
rename"
subcommand can be used to rename any conflicting snapshots.
zfs rename filesystem|
volume|
snapshot
filesystem|
volume|
snapshot
Renames the given dataset. The new target can
be located anywhere in the ZFS hierarchy, with the exception of
snapshots. Snapshots can only be renamed within the parent file system or
volume. When renaming a snapshot, the parent file system of the snapshot does
not need to be specified as part of the second argument. Renamed file systems
can inherit new mount points, in which case they are unmounted and remounted
at the new mount point.
zfs snapshot [
-r]
filesystem@name|
volume@name
Creates a snapshot with the given name. See
the "Snapshots" section for details.
-r
Recursively create snapshots of all descendant
datasets. Snapshots are taken atomically, so that all recursive snapshots
correspond to the same moment in time.
zfs rollback [
-rRf]
snapshot
Roll back the given dataset to a previous
snapshot. When a dataset is rolled back, all data that has changed since the
snapshot is discarded, and the dataset reverts to the state at the time of the
snapshot. By default, the command refuses to roll back to a snapshot other
than the most recent one. In order to do so, all intermediate snapshots must
be destroyed by specifying the
-r option. The file system is unmounted
and remounted, if necessary.
-r
Recursively destroy any snapshots more recent
than the one specified.
-R
Recursively destroy any more recent snapshots,
as well as any clones of those snapshots.
-f
Force an unmount of any file systems using the
" unmount -f" command.
zfs list [
-rH] [
-o prop[,
prop]
]... [
-t type[,
type]...] [
-s prop
[
-s prop]... [
-S prop [
-S prop]...
[
filesystem|
volume|
snapshot|
/pathname|.
/pathname
...
Lists the property information for the given
datasets in tabular form. If specified, you can list property information by
the absolute pathname or the relative pathname. By default, all datasets are
displayed and contain the following fields:
name,used,available,referenced,mountpoint
-H
Used for scripting mode. Do not print headers
and separate fields by a single tab instead of arbitrary whitespace.
-r
Recursively display any children of the
dataset on the command line.
-o prop
A comma-separated list of properties to
display. The property must be one of the properties described in the
"Native Properties" section, or the special value "name"
to display the dataset name.
-s prop
A property to use for sorting the output by
column in ascending order based on the value of the property. The property
must be one of the properties described in the "Properties" section,
or the special value "name" to sort by the dataset name. Multiple
properties can be specified at one time using multiple
-s property
options. Multiple
-s options are evaluated from left to right in
decreasing order of importance.
The following is a list of sorting criteria:
- o
- Numeric types sort in numeric order.
- o
- String types sort in alphabetical order.
- o
- Types inappropriate for a row sort that row to the literal
bottom, regardless of the specified ordering.
- o
- If no sorting options are specified the existing behavior
of " zfs list" is preserved.
-S prop
Same as the -s option, but sorts by
property in descending order.
-t type
A comma-separated list of types to display,
where "type" is one of "filesystem", "snapshot"
or "volume". For example, specifying " -t snapshot"
displays only snapshots.
zfs set property=
value
filesystem|
volume ...
Sets the property to the given value for each
dataset. Only some properties can be edited. See the "Properties"
section for more information on what properties can be set and acceptable
values. Numeric values can be specified as exact values, or in a
human-readable form with a suffix of "B", "K",
"M", "G", "T", "P", "E",
"Z" (for bytes, Kbytes, Mbytes, gigabytes, terabytes, petabytes,
exabytes, or zettabytes, respectively). Properties cannot be set on
snapshots.
zfs get [
-rHp] [
-o field[,
field]...]
[
-s source[,
source]...]
all |
property[,
property]...
filesystem|
volume|
snapshot ...
Displays properties for the given datasets. If
no datasets are specified, then the command displays properties for all
datasets on the system. For each property, the following columns are
displayed:
name Dataset name
property Property name
value Property value
source Property source. Can either be local, default,
temporary, inherited, or none (-).
All columns are displayed by default, though this can be controlled by using the
-o option. This command takes a comma-separated list of properties as
described in the "Native Properties" and "User Properties"
sections.
The special value "all" can be used to display all properties for the
given dataset.
-r
Recursively display properties for any
children.
-H
Display output in a form more easily parsed
by scripts. Any headers are omitted, and fields are explicitly separated by a
single tab instead of an arbitrary amount of space.
-o field
A comma-separated list of columns to display.
"name,property,value,source" is the default value.
-s source
A comma-separated list of sources to display.
Those properties coming from a source other than those in this list are
ignored. Each source must be one of the following:
"local,default,inherited,temporary,none". The default value is all
sources.
-p
Display numbers in parsable (exact)
values.
zfs inherit [
-r]
property
filesystem|
volume ...
Clears the specified property, causing it to
be inherited from an ancestor. If no ancestor has the property set, then the
default value is used. See the "Properties" section for a listing of
default values, and details on which properties can be inherited.
-r
Recursively inherit the given property for all
children.
zfs mount
Displays all ZFS file systems currently
mounted.
zfs mount[
-o opts] [
-O]
-a
Mounts all available
ZFS file systems.
Invoked automatically as part of the boot process.
-o opts
An optional comma-separated list of mount
options to use temporarily for the duration of the mount. See the
"Temporary Mount Point Properties" section for details.
-O
Perform an overlay mount. See
mount(1M) for more information.
zfs mount [
-o opts] [
-O]
filesystem
Mounts a specific
ZFS file system. This
is typically not necessary, as file systems are automatically mounted when
they are created or the mountpoint property has changed. See the "Mount
Points" section for details.
-o opts
An optional comma-separated list of mount
options to use temporarily for the duration of the mount. See the
"Temporary Mount Point Properties" section for details.
-O
Perform an overlay mount. See
mount(1M) for more information.
zfs unmount -a
Unmounts all currently mounted ZFS file
systems. Invoked automatically as part of the shutdown process.
zfs unmount [
-f]
filesystem|
mountpoint
Unmounts the given file system. The command
can also be given a path to a
ZFS file system mount point on the
system.
-f
Forcefully unmount the file system, even if it
is currently in use.
zfs share -a
Shares all available ZFS file systems.
This is invoked automatically as part of the boot process.
zfs share filesystem
Shares a specific ZFS file system
according to the "sharenfs" property. File systems are shared when
the "sharenfs" property is set.
zfs unshare -a
Unshares all currently shared ZFS file
systems. This is invoked automatically as part of the shutdown process.
zfs unshare [
-F]
filesystem|
mountpoint
Unshares the given file system. The command
can also be given a path to a
ZFS file system shared on the system.
-F
Forcefully unshare the file system, even if it
is currently in use.
zfs send [
-i snapshot1]
snapshot2
Creates a stream representation of snapshot2,
which is written to standard output. The output can be redirected to a file or
to a different system (for example, using
ssh(1). By default, a full
stream is generated.
-i snapshot1
Generate an incremental stream from
snapshot1 to snapshot2. The incremental source snapshot1
can be specified as the last component of the snapshot name (for example, the
part after the "@"), and it is assumed to be from the same file
system as snapshot2.
The format of the stream is evolving. No backwards compatibility is guaranteed.
You may not be able to receive your streams on future versions of
ZFS.
zfs receive [
-vnF]
filesystem|
volume|
snapshot
zfs receive [
-vnF]
-d filesystem
Creates a snapshot whose contents are as
specified in the stream provided on standard input. If a full stream is
received, then a new file system is created as well. Streams are created using
the "
zfs send" subcommand, which by default creates a full
stream. "
zfs recv" can be used as an alias for "
zfs
receive".
If an incremental stream is received, then the destination file system must
already exist, and its most recent snapshot must match the incremental
stream's source. The destination file system and all of its child file systems
are unmounted and cannot be accessed during the receive operation.
The name of the snapshot (and file system, if a full stream is received) that
this subcommand creates depends on the argument type and the
-d option.
If the argument is a snapshot name, the specified
snapshot is created. If
the argument is a file system or volume name, a snapshot with the same name as
the sent snapshot is created within the specified
filesystem or
volume. If the
-d option is specified, the snapshot name is
determined by appending the sent snapshot's name to the specified
filesystem. If the
-d option is specified, any required file
systems within the specified one are created.
-d
Use the name of the sent snapshot to determine
the name of the new snapshot as described in the paragraph above.
-v
Print verbose information about the stream and
the time required to perform the receive operation.
-n
Do not actually receive the stream. This can
be useful in conjunction with the -v option to determine what name the
receive operation would use.
-F
Force a rollback of the filesystem to
the most recent snapshot before performing the receive operation.
zfs jail jailid filesystem
Attaches the given file system to the given
jail. From now on this file system tree can be managed from within a jail if
the " jailed" property has been set. To use this
functionality, sysctl security.jail.enforce_statfs should be set to 0
and sysctl security.jail.mount_allowed should be set to 1.
zfs unjail jailid filesystem
Detaches the given file system from the given
jail.
EXAMPLES
Example 1 Creating a ZFS File System Hierarchy
The following commands create a file system named "
pool/home"
and a file system named "
pool/home/bob". The mount point
"
/export/home" is set for the parent file system, and
automatically inherited by the child file system.
# zfs create pool/home
# zfs set mountpoint=/export/home pool/home
# zfs create pool/home/bob
Example 2 Creating a ZFS Snapshot
The following command creates a snapshot named "yesterday". This
snapshot is mounted on demand in the ".zfs/snapshot" directory at
the root of the "
pool/home/bob" file system.
# zfs snapshot pool/home/bob@yesterday
Example 3 Taking and destroying multiple snapshots
The following command creates snapshots named "
yesterday" of
"
pool/home" and all of its descendant file systems. Each
snapshot is mounted on demand in the ".zfs/snapshot" directory at
the root of its file system. The second command destroys the newly created
snapshots.
# zfs snapshot -r pool/home@yesterday
# zfs destroy -r pool/home@yesterday
Example 4 Turning Off Compression
The following commands turn compression off for all file systems under "
pool/home", but explicitly turns it on for
"
pool/home/anne".
# zfs set compression=off pool/home
# zfs set compression=on pool/home/anne
Example 5 Listing ZFS Datasets
The following command lists all active file systems and volumes in the system.
# zfs list
NAME USED AVAIL REFER MOUNTPOINT
pool 100G 60G - /pool
pool/home 100G 60G - /export/home
pool/home/bob 40G 60G 40G /export/home/bob
pool/home/bob@yesterday 3M - 40G -
pool/home/anne 60G 60G 40G /export/home/anne
Example 6 Setting a Quota on a ZFS File System
The following command sets a quota of 50 gbytes for "
pool/home/bob".
# zfs set quota=50G pool/home/bob
Example 7 Listing ZFS Properties
The following command lists all properties for "
pool/home/bob".
# zfs get all pool/home/bob
NAME PROPERTY VALUE SOURCE
pool/home/bob type filesystem -
pool/home/bob creation Fri Feb 23 14:20 2007 -
pool/home/bob used 24.5K -
pool/home/bob available 50.0G -
pool/home/bob referenced 24.5K -
pool/home/bob compressratio 1.00x -
pool/home/bob mounted yes -
pool/home/bob quota 50G local
pool/home/bob reservation none default
pool/home/bob recordsize 128K default
pool/home/bob mountpoint /pool/home/bob default
pool/home/bob sharenfs off default
pool/home/bob shareiscsi off default
pool/home/bob checksum on default
pool/home/bob compression off default
pool/home/bob atime on default
pool/home/bob devices on default
pool/home/bob exec on default
pool/home/bob setuid on default
pool/home/bob readonly off default
pool/home/bob zoned off default
pool/home/bob snapdir hidden default
pool/home/bob aclmode groupmask default
pool/home/bob aclinherit secure default
pool/home/bob canmount on default
pool/home/bob xattr on default
The following command gets a single property value.
# zfs get -H -o value compression pool/home/bob
on
The following command lists all properties with local settings for "
pool/home/bob".
# zfs get -r -s local -o name,property,value all pool/home/bob
NAME PROPERTY VALUE
pool compression on
pool/home checksum off
Example 8 Rolling Back a ZFS File System
The following command reverts the contents of "
pool/home/anne"
to the snapshot named "
yesterday", deleting all intermediate
snapshots.
# zfs rollback -r pool/home/anne@yesterday
Example 9 Creating a ZFS Clone
The following command creates a writable file system whose initial contents are
the same as "
pool/home/bob@yesterday".
# zfs clone pool/home/bob@yesterday pool/clone
Example 10 Promoting a ZFS Clone
The following commands illustrate how to test out changes to a file system, and
then replace the original file system with the changed one, using clones,
clone promotion, and renaming:
# zfs create pool/project/production
populate /pool/project/production with data
# zfs snapshot pool/project/production@today
# zfs clone pool/project/production@today pool/project/beta
make changes to /pool/project/beta and test them
# zfs promote pool/project/beta
# zfs rename pool/project/production pool/project/legacy
# zfs rename pool/project/beta pool/project/production
once the legacy version is no longer needed, it can be
destroyed
# zfs destroy pool/project/legacy
Example 11 Inheriting ZFS Properties
The following command causes "
pool/home/bob" and
"
pool/home/anne" to inherit the "checksum" property
from their parent.
# zfs inherit checksum pool/home/bob pool/home/anne
Example 12 Remotely Replicating ZFS Data
The following commands send a full stream and then an incremental stream to a
remote machine, restoring them into "
poolB/received/fs@a"
and "
poolB/received/fs@b", respectively.
"
poolB" must contain the file system "
poolB/received", and must not initially contain "
poolB/received/fs".
# zfs send pool/fs@a | \
ssh host zfs receive poolB/received/fs@a
# zfs send -i a pool/fs@b | ssh host \
zfs receive poolB/received/fs
Example 13 Using the zfs receive -d Option
The following command sends a full stream of "
poolA/fsA/fsB@snap" to a remote machine, receiving it into "
poolB/received/fsA/fsB@snap". The "
fsA/fsB@snap"
portion of the received snapshot's name is determined from the name of the
sent snapshot. "
poolB" must contain the file system
"
poolB/received". If "
poolB/received/fsA"
does not exist, it will be created as an empty file system.
# zfs send poolA/fsA/fsB@snap | \
ssh host zfs receive -d poolB/received
Example 14 Creating a ZFS volume as a Swap Device
The following example shows how to create a 5-Gbyte ZFS volume and then add the
volume as a swap device.
# zfs create -V 5gb tank/vol
# swap -a /dev/zvol/dsk/tank/vol
Example 15 Setting User Properties
The following example sets the user defined "com.example:department"
property for a dataset.
# zfs set com.example:department=12345 tank/accounting
Example 16 Creating a ZFS Volume as a iSCSI Target Device
The following example shows how to create a
ZFS volume as an
iSCSI
target.
# zfs create -V 2g pool/volumes/vol1
# zfs set shareiscsi=on pool/volumes/vol1
# iscsitadm list target
Target: pool/volumes/vol1
iSCSI Name:
iqn.1986-03.com.sun:02:7b4b02a6-3277-eb1b-e686-a24762c52a8c
Connections: 0
After the
iSCSI target is created, set up the
iSCSI initiator. For
more information about the Solaris
iSCSI initiator, see the Solaris
Administration Guide: Devices and File Systems.
EXIT STATUS
The following exit values are returned:
0
Successful completion.
1
An error occurred.
2
Invalid command line options were
specified.
ATTRIBUTES
See
attributes(5) for descriptions of the following attributes:
ATTRIBUTE TYPE |
ATTRIBUTE VALUE |
|
Availability |
SUNWzfsu |
|
Interface Stability |
Evolving |
SEE ALSO
gzip(1),
ssh(1),
mount(1M),
share(1M),
unshare(1M),
zonecfg(1M),
zpool(1M),
chmod(2),
stat(2),
fsync(3c),
dfstab(4),
attributes(5)