zpool —
configures ZFS storage pools
zpool |
add
[-fn
]
pool vdev ... |
zpool |
attach
[-f
]
pool device new_device |
zpool |
checkpoint
[-d,
--discard
]
pool |
zpool |
clear
[]
pool
[device ] |
zpool |
create
[-fnd
]
[-o
property=value
]
...
[-O
file-system-property=value
]
...
[-m
mountpoint
]
[-R
root
]
[-t
tempname
]
pool vdev ... |
zpool |
export
[-f
]
pool ... |
zpool |
get
[-Hp
]
[]
all |
property[,... ]
pool ... |
zpool |
history
[-il
]
[pool ]
... |
zpool |
import
[-d
dir |
-c
cachefile
]
[-D
] |
zpool |
import
[-o
mntopts
]
[-o
property=value
]
...
[--rewind-to-checkpoint
]
[-d
dir |
-c
cachefile
]
[-D
]
[-f
]
[-m
]
[-N
]
[-R
root
]
[]
-a |
zpool |
import
[-o
mntopts
]
[-o
property=value
]
...
[--rewind-to-checkpoint
]
[-d
dir |
-c
cachefile
]
[-D
]
[-f
]
[-m
]
[-N
]
[-R
root
]
[-t
]
[]
pool |
id
[newpool ] |
zpool |
initialize
[-cs
]
pool
[device... ] |
zpool |
iostat
[-T
d|u
]
[-v
]
[pool ]
... |
zpool |
labelclear
[-f
]
device |
zpool |
list
[-Hpv
]
[]
[-T
d|u
]
[pool ]
...
[] |
zpool |
offline
[-t
]
pool device ... |
zpool |
online
[-e
]
pool device ... |
zpool |
remove
[-np
]
pool device ... |
zpool |
replace
[-f
]
pool device
[new_device ] |
zpool |
scrub
[-s |
-p
]
pool ... |
zpool |
set
property=value
pool |
zpool |
split
[-n
]
[-R
altroot
]
[-o
mntopts
]
[-o
property=value
]
pool newpool
[device ... ] |
zpool |
status
[-vx
]
[-T
d|u
]
[pool ]
...
[] |
zpool |
upgrade
[-V
version
]
-a | pool
... |
The
zpool command configures ZFS storage
pools. A storage pool is a collection of devices that provides physical
storage and data replication for ZFS datasets.
All datasets within a storage pool share the same space. See
zfs(8)
for information on managing datasets.
A “virtual device” (
vdev) describes a
single device or a collection of devices organized according to certain
performance and fault characteristics. The following virtual devices are
supported:
- disk
- A block device, typically located under
/dev. ZFS can use individual slices or
partitions, though the recommended mode of operation is to use whole
disks. A disk can be specified by a full path to the device or the
geom(4)
provider name. When given a whole disk, ZFS automatically labels the disk,
if necessary.
- file
- A regular file. The use of files as a backing store is strongly
discouraged. It is designed primarily for experimental purposes, as the
fault tolerance of a file is only as good the file system of which it is a
part. A file must be specified by a full path.
- mirror
- A mirror of two or more devices. Data is replicated in an identical
fashion across all components of a mirror. A mirror with
N disks of size
X can hold X
bytes and can withstand (N-1) devices failing
before data integrity is compromised.
- raidz
- (or raidz1 raidz2 raidz3). A variation on
RAID-5 that allows for better distribution of
parity and eliminates the
“RAID-5” write hole (in which
data and parity become inconsistent after a power loss). Data and parity
is striped across all disks within a raidz group.
A raidz group can have single-, double- , or triple
parity, meaning that the raidz group can sustain
one, two, or three failures, respectively, without losing any data. The
raidz1 vdev type
specifies a single-parity raidz group; the
raidz2 vdev type
specifies a double-parity raidz group; and the
raidz3 vdev type
specifies a triple-parity raidz group. The
raidz vdev type is an
alias for raidz1.
A raidz group with N
disks of size X with
P parity disks can hold approximately
(N-P)*X bytes and can withstand
P device(s) failing before data integrity is
compromised. The minimum number of devices in a
raidz group is one more than the number of parity
disks. The recommended number is between 3 and 9 to help increase
performance.
- spare
- A special pseudo-vdev
which keeps track of available hot spares for a pool. For more
information, see the
“Hot Spares”
section.
- log
- A separate-intent log device. If more than one log device is specified,
then writes are load-balanced between devices. Log devices can be
mirrored. However, raidz
vdev types are not supported for the intent log.
For more information, see the
“Intent Log”
section.
- cache
- A device used to cache storage pool data. A cache device cannot be
configured as a mirror or raidz group. For more
information, see the
“Cache
Devices” section.
Virtual devices cannot be nested, so a mirror or
raidz
virtual device can only contain files or disks. Mirrors of mirrors (or other
combinations) are not allowed.
A pool can have any number of virtual devices at the top of the configuration
(known as “root”
vdevs). Data is
dynamically distributed across all top-level devices to balance data among
devices. As new virtual devices are added, ZFS automatically places data on
the newly available devices.
Virtual devices are specified one at a time on the command line, separated by
whitespace. The keywords “mirror” and “raidz” are
used to distinguish where a group ends and another begins. For example, the
following creates two root
vdevs, each a mirror of two
disks:
# zpool create mypool mirror da0 da1 mirror da2 da3
ZFS supports a rich set of mechanisms for handling device failure and data
corruption. All metadata and data is checksummed, and ZFS automatically
repairs bad data from a good copy when corruption is detected.
In order to take advantage of these features, a pool must make use of some form
of redundancy, using either mirrored or
raidz groups.
While ZFS supports running in a non-redundant configuration, where each root
vdev is simply a disk or file, this is strongly
discouraged. A single case of bit corruption can render some or all of your
data unavailable.
A pool's health status is described by one of three states: online, degraded, or
faulted. An online pool has all devices operating normally. A degraded pool is
one in which one or more devices have failed, but the data is still available
due to a redundant configuration. A faulted pool has corrupted metadata, or
one or more faulted devices, and insufficient replicas to continue
functioning.
The health of the top-level
vdev, such as mirror or
raidz device, is potentially impacted by the state of
its associated
vdevs, or component devices. A
top-level
vdev or component device is in one of the
following states:
- DEGRADED
- One or more top-level vdevs is in the degraded
state because one or more component devices are offline. Sufficient
replicas exist to continue functioning.
One or more component devices is in the degraded or faulted state, but
sufficient replicas exist to continue functioning. The underlying
conditions are as follows:
- The number of checksum errors exceeds acceptable levels and the device
is degraded as an indication that something may be wrong. ZFS
continues to use the device as necessary.
- The number of I/O errors exceeds acceptable levels. The device could
not be marked as faulted because there are insufficient replicas to
continue functioning.
- FAULTED
- One or more top-level vdevs is in the faulted
state because one or more component devices are offline. Insufficient
replicas exist to continue functioning.
One or more component devices is in the faulted state, and insufficient
replicas exist to continue functioning. The underlying conditions are as
follows:
- The device could be opened, but the contents did not match expected
values.
- The number of I/O errors exceeds acceptable levels and the device is
faulted to prevent further use of the device.
- OFFLINE
- The device was explicitly taken offline by the
“
zpool
offline” command.
- ONLINE
- The device is online and functioning.
- REMOVED
- The device was physically removed while the system was running. Device
removal detection is hardware-dependent and may not be supported on all
platforms.
- UNAVAIL
- The device could not be opened. If a pool is imported when a device was
unavailable, then the device will be identified by a unique identifier
instead of its path since the path was never correct in the first
place.
If a device is removed and later reattached to the system, ZFS attempts to put
the device online automatically. Device attach detection is hardware-dependent
and might not be supported on all platforms.
ZFS allows devices to be associated with pools as “hot spares”.
These devices are not actively used in the pool, but when an active device
fails, it is automatically replaced by a hot spare. To create a pool with hot
spares, specify a “spare”
vdev with any
number of devices. For example,
# zpool create pool mirror da0 da1 spare da2 da3
Spares can be shared across multiple pools, and can be added with the
“
zpool
add” command and removed with the
“
zpool
remove” command. Once a spare
replacement is initiated, a new "spare"
vdev
is created within the configuration that will remain there until the original
device is replaced. At this point, the hot spare becomes available again if
another device fails.
If a pool has a shared spare that is currently being used, the pool can not be
exported since other pools may use this shared spare, which may lead to
potential data corruption.
An in-progress spare replacement can be cancelled by detaching the hot spare. If
the original faulted device is detached, then the hot spare assumes its place
in the configuration, and is removed from the spare list of all active pools.
Spares cannot replace log devices.
This feature requires a userland helper. FreeBSD provides
zfsd(8)
for this purpose. It must be manually enabled by adding
zfsd_enable="YES" to
/etc/rc.conf.
The ZFS Intent Log (ZIL) satisfies POSIX requirements for synchronous
transactions. For instance, databases often require their transactions to be
on stable storage devices when returning from a system call. NFS and other
applications can also use
fsync(2)
to ensure data stability. By default, the intent log is allocated from blocks
within the main pool. However, it might be possible to get better performance
using separate intent log devices such as NVRAM or a dedicated disk. For
example:
# zpool create pool da0 da1 log da2
Multiple log devices can also be specified, and they can be mirrored. See the
EXAMPLES section for an example
of mirroring multiple log devices.
Log devices can be added, replaced, attached, detached, imported and exported as
part of the larger pool. Mirrored devices can be removed by specifying the
top-level mirror vdev.
Devices can be added to a storage pool as "cache devices." These
devices provide an additional layer of caching between main memory and disk.
For read-heavy workloads, where the working set size is much larger than what
can be cached in main memory, using cache devices allow much more of this
working set to be served from low latency media. Using cache devices provides
the greatest performance improvement for random read-workloads of mostly
static content.
To create a pool with cache devices, specify a "cache"
vdev with any number of devices. For example:
# zpool create pool da0 da1 cache da2 da3
Cache devices cannot be mirrored or part of a
raidz
configuration. If a read error is encountered on a cache device, that read I/O
is reissued to the original storage pool device, which might be part of a
mirrored or
raidz configuration.
The content of the cache devices is considered volatile, as is the case with
other system caches.
Before starting critical procedures that include destructive actions (e.g
zfs
destroy ), an administrator can checkpoint
the pool's state and in the case of a mistake or failure, rewind the entire
pool back to the checkpoint. Otherwise, the checkpoint can be discarded when
the procedure has completed successfully.
A pool checkpoint can be thought of as a pool-wide snapshot and should be used
with care as it contains every part of the pool's state, from properties to
vdev configuration. Thus, while a pool has a checkpoint certain operations are
not allowed. Specifically, vdev removal/attach/detach, mirror splitting, and
changing the pool's guid. Adding a new vdev is supported but in the case of a
rewind it will have to be added again. Finally, users of this feature should
keep in mind that scrubs in a pool that has a checkpoint do not repair
checkpointed data.
To create a checkpoint for a pool:
To later rewind to its checkpointed state, you need to first export it and then
rewind it during import:
# zpool export pool
# zpool import --rewind-to-checkpoint pool
To discard the checkpoint from a pool:
# zpool checkpoint -d pool
Dataset reservations (controlled by the
reservation or
refreservation zfs properties) may be
unenforceable while a checkpoint exists, because the checkpoint is allowed to
consume the dataset's reservation. Finally, data that is part of the
checkpoint but has been freed in the current state of the pool won't be
scanned during a scrub.
Each pool has several properties associated with it. Some properties are
read-only statistics while others are configurable and change the behavior of
the pool. The following are read-only properties:
- alloc
- Amount of storage space within the pool that has been physically
allocated.
- capacity
- Percentage of pool space used. This property can also be referred to by
its shortened column name, "cap".
- comment
- A text string consisting of printable ASCII characters that will be stored
such that it is available even if the pool becomes faulted. An
administrator can provide additional information about a pool using this
property.
- dedupratio
- The deduplication ratio specified for a pool, expressed as a multiplier.
For example, a dedupratio value of 1.76
indicates that 1.76 units of data were stored but only 1 unit of disk
space was actually consumed. See
zfs(8)
for a description of the deduplication feature.
- expandsize
- Amount of uninitialized space within the pool or device that can be used
to increase the total capacity of the pool. Uninitialized space consists
of any space on an EFI labeled vdev which has not been brought online
(i.e. zpool online -e). This space occurs when a LUN is dynamically
expanded.
- fragmentation
- The amount of fragmentation in the pool.
- free
- Number of blocks within the pool that are not allocated.
- freeing
- After a file system or snapshot is destroyed, the space it was using is
returned to the pool asynchronously. freeing
is the amount of space remaining to be reclaimed. Over time
freeing will decrease while
free increases.
- guid
- A unique identifier for the pool.
- health
- The current health of the pool. Health can be
“ONLINE”,
“DEGRADED”,
“FAULTED”,
“OFFLINE”,
“REMOVED”, or
“UNAVAIL”.
- size
- Total size of the storage pool.
- unsupported@feature_guid
- Information about unsupported features that are enabled on the pool. See
zpool-features(7)
for details.
- used
- Amount of storage space used within the pool.
The space usage properties report actual physical space available to the storage
pool. The physical space can be different from the total amount of space that
any contained datasets can actually use. The amount of space used in a
raidz configuration depends on the characteristics of
the data being written. In addition, ZFS reserves some space for internal
accounting that the
zfs(8)
command takes into account, but the
zpool(8)
command does not. For non-full pools of a reasonable size, these effects
should be invisible. For small pools, or pools that are close to being
completely full, these discrepancies may become more noticeable.
The following property can be set at creation time and import time:
- altroot
- Alternate root directory. If set, this directory is prepended to any mount
points within the pool. This can be used when examining an unknown pool
where the mount points cannot be trusted, or in an alternate boot
environment, where the typical paths are not valid.
altroot is not a persistent property. It is
valid only while the system is up. Setting
altroot defaults to using
cachefile=none, though this may be
overridden using an explicit setting.
The following property can only be set at import time:
- readonly=
on
|
off
- If set to
on, pool will be imported in
read-only mode with the following restrictions:
- Synchronous data in the intent log will not be accessible
- Properties of the pool can not be changed
- Datasets of this pool can only be mounted read-only
- To write to a read-only pool, a export and import of the pool is
required.
This property can also be referred to by its shortened column name,
rdonly.
The following properties can be set at creation time and import time, and later
changed with the
zpool set command:
- autoexpand=
on
|
off
- Controls automatic pool expansion when the underlying LUN is grown. If set
to “
on”, the pool will be
resized according to the size of the expanded device. If the device is
part of a mirror or raidz then all devices within
that mirror/raidz group
must be expanded before the new space is made available to the pool. The
default behavior is “off”. This property can also be
referred to by its shortened column name,
expand.
- autoreplace=
on
|
off
- Controls automatic device replacement. If set to
“
off”, device replacement
must be initiated by the administrator by using the
“zpool
replace” command. If set to
“on”, any new device,
found in the same physical location as a device that previously belonged
to the pool, is automatically formatted and replaced. The default behavior
is “off”. This property
can also be referred to by its shortened column name,
"replace".
- bootfs=pool/dataset
- Identifies the default bootable dataset for the root pool. This property
is expected to be set mainly by the installation and upgrade
programs.
- cachefile=path
|
none
- Controls the location of where the pool configuration is cached.
Discovering all pools on system startup requires a cached copy of the
configuration data that is stored on the root file system. All pools in
this cache are automatically imported when the system boots. Some
environments, such as install and clustering, need to cache this
information in a different location so that pools are not automatically
imported. Setting this property caches the pool configuration in a
different location that can later be imported with
“
zpool
import
-c”. Setting it to the special
value “none” creates a
temporary pool that is never cached, and the special value
'' (empty string) uses the default
location.
- comment=text
- A text string consisting of printable ASCII characters that will be stored
such that it is available even if the pool becomes faulted. An
administrator can provide additional information about a pool using this
property.
- dedupditto=number
- Threshold for the number of block ditto copies. If the reference count for
a deduplicated block increases above this number, a new ditto copy of this
block is automatically stored. Default setting is
0 which causes no ditto copies to be
created for deduplicated blocks. The miniumum legal nonzero setting is
100.
- delegation=
on
|
off
- Controls whether a non-privileged user is granted access based on the
dataset permissions defined on the dataset. See
zfs(8)
for more information on ZFS delegated administration.
- failmode=
wait
|
continue
|
panic
- Controls the system behavior in the event of catastrophic pool failure.
This condition is typically a result of a loss of connectivity to the
underlying storage device(s) or a failure of all devices within the pool.
The behavior of such an event is determined as follows:
- wait
- Blocks all I/O access until the device connectivity is recovered and
the errors are cleared. This is the default behavior.
- continue
- Returns EIO to any new write I/O requests
but allows reads to any of the remaining healthy devices. Any write
requests that have yet to be committed to disk would be blocked.
- panic
- Prints out a message to the console and generates a system crash
dump.
- feature@feature_name=enabled
- The value of this property is the current state of
feature_name. The only valid value when
setting this property is enabled which moves
feature_name to the enabled state. See
zpool-features(7)
for details on feature states.
- listsnaps=
on
|
off
- Controls whether information about snapshots associated with this pool is
output when “
zfs
list” is run without the
-t option. The default value is
off.
- version=version
- The current on-disk version of the pool. This can be increased, but never
decreased. The preferred method of updating pools is with the
“
zpool
upgrade” command, though this
property can be used when a specific version is needed for backwards
compatibility. Once feature flags is enabled on a pool this property will
no longer have a value.
All subcommands that modify state are logged persistently to the pool in their
original form.
The
zpool command provides subcommands to
create and destroy storage pools, add capacity to storage pools, and provide
information about the storage pools. The following subcommands are supported:
zpool
[-?
]-
Displays a help message.
zpool
add
[-fn
]
pool vdev ...-
Adds the specified virtual devices to the given pool. The
vdev specification is described in the
“Virtual
Devices” section. The behavior of the
-f option, and the device checks
performed are described in the
“zpool
create” subcommand.
-f- Forces use of vdev, even if they
appear in use or specify a conflicting replication level. Not all
devices can be overridden in this manner.
-n- Displays the configuration that would be used without actually adding
the vdevs. The actual pool creation
can still fail due to insufficient privileges or device sharing.
Do not add a disk that is currently configured as a quorum device to a
zpool. After a disk is in the pool, that disk can then be configured
as a quorum device.
zpool
attach
[-f
]
pool device new_device-
Attaches new_device to an existing
zpool device. The existing device cannot be
part of a raidz configuration. If
device is not currently part of a
mirrored configuration, device
automatically transforms into a two-way mirror of
device and
new_device. If
device is part of a two-way mirror,
attaching new_device creates a three-way
mirror, and so on. In either case,
new_device begins to resilver
immediately.
-f- Forces use of new_device, even if its
appears to be in use. Not all devices can be overridden in this
manner.
zpool
checkpoint
[-d,
--discard
]
pool- Checkpoints the current state of pool ,
which can be later restored by
zpool
import --rewind-to-checkpoint. The
existence of a checkpoint in a pool prohibits the following
zpool commands:
remove,
attach,
detach,
split, and
reguid. In addition, it may break
reservation boundaries if the pool lacks free space. The
zpool
status command indicates the existence
of a checkpoint or the progress of discarding a checkpoint from a pool.
The zpool
list command reports how much space the
checkpoint takes from the pool.
-d,
--discard- Discards an existing checkpoint from
pool.
zpool
clear
[]
pool
[device
]-
Clears device errors in a pool. If no arguments are specified, all device
errors within the pool are cleared. If one or more devices is specified,
only those errors associated with the specified device or devices are
cleared.
-F- Initiates recovery mode for an unopenable pool. Attempts to discard
the last few transactions in the pool to return it to an openable
state. Not all damaged pools can be recovered by using this option. If
successful, the data from the discarded transactions is irretrievably
lost.
-n- Used in combination with the
-F
flag. Check whether discarding transactions would make the pool
openable, but do not actually discard any transactions.
zpool
create
[-fnd
]
[-o
property=value
]
...
[-O
file-system-property=value
]
...
[-m
mountpoint
]
[-R
root
]
[-t
tempname
]
pool vdev ...-
Creates a new storage pool containing the virtual devices specified on the
command line. The pool name must begin with a letter, and can only contain
alphanumeric characters as well as underscore ("_"), dash
("-"), and period ("."). The pool names
"mirror", "raidz", "spare" and
"log" are reserved, as are names beginning with the pattern
"c[0-9]". The vdev specification is
described in the
“Virtual
Devices” section.
The command verifies that each device specified is accessible and not
currently in use by another subsystem. There are some uses, such as being
currently mounted, or specified as the dedicated dump device, that
prevents a device from ever being used by ZFS Other uses, such as having a
preexisting UFS file system, can be
overridden with the
-f option.
The command also checks that the replication strategy for the pool is
consistent. An attempt to combine redundant and non-redundant storage in a
single pool, or to mix disks and files, results in an error unless
-f is specified. The use of differently
sized devices within a single raidz or mirror
group is also flagged as an error unless
-f is specified.
Unless the -R option is specified, the
default mount point is
“/pool”. The mount point
must not exist or must be empty, or else the root dataset cannot be
mounted. This can be overridden with the
-m option.
By default all supported features are enabled on the new pool unless the
-d option is specified.
-f- Forces use of vdevs, even if they
appear in use or specify a conflicting replication level. Not all
devices can be overridden in this manner.
-n- Displays the configuration that would be used without actually
creating the pool. The actual pool creation can still fail due to
insufficient privileges or device sharing.
-d- Do not enable any features on the new pool. Individual features can be
enabled by setting their corresponding properties to
enabled with the
-o option. See
zpool-features(7)
for details about feature properties.
-o
property=value
[-o
property=value
]
...- Sets the given pool properties. See the
“Properties”
section for a list of valid properties that can be set.
-O
file-system-property=value
[-O
file-system-property=value
]
...- Sets the given file system properties in the root file system of the
pool. See
zfs(8)
Properties for a list of valid properties that can be set.
-R
root- Equivalent to “
-o
cachefile=none,altroot=root”
-m
mountpoint- Sets the mount point for the root dataset. The default mount point is
“/pool” or
“
altroot/pool”
if altroot is specified. The mount point
must be an absolute path,
“legacy”, or
“none”. For more
information on dataset mount points, see
zfs(8).
-t
tempname- Sets the in-core pool name to
tempname while the on-disk name
will be the name specified as the pool name
pool. This will set the default
cachefile property to
none. This is intended to handle name
space collisions when creating pools for other systems, such as
virtual machines or physical machines whose pools live on network
block devices.
zpool
destroy
[-f
]
pool-
Destroys the given pool, freeing up any devices for other use. This command
tries to unmount any active datasets before destroying the pool.
-f- Forces any active datasets contained within the pool to be
unmounted.
zpool
detach pool
device-
Detaches device from a mirror. The
operation is refused if there are no other valid replicas of the
data.
zpool
export
[-f
]
pool ...-
Exports the given pools from the system. All devices are marked as exported,
but are still considered in use by other subsystems. The devices can be
moved between systems (even those of different endianness) and imported as
long as a sufficient number of devices are present.
Before exporting the pool, all datasets within the pool are unmounted. A
pool can not be exported if it has a shared spare that is currently being
used.
For pools to be portable, you must give the
zpool command whole disks, not just
slices, so that ZFS can label the disks with portable
EFI labels. Otherwise, disk drivers on
platforms of different endianness will not recognize the disks.
-f- Forcefully unmount all datasets, using the
“
unmount
-f” command.
This command will forcefully export the pool even if it has a shared
spare that is currently being used. This may lead to potential data
corruption.
zpool
get
[-Hp
]
[]
all |
property[,...
]
pool ...-
Retrieves the given list of properties (or all properties if
“
all” is used) for the
specified storage pool(s). These properties are displayed with the
following fields:
| name |
Name of storage pool |
| property |
Property name |
| value |
Property value |
| source |
Property source, either 'default' or 'local'. |
See the
“Properties”
section for more information on the available pool properties.
-H- Scripted mode. Do not display headers, and separate fields by a single tab
instead of arbitrary space.
-p- Display numbers in parsable (exact) values.
-o
field- A comma-separated list of columns to display.
name,property,value,source
is the default value.
zpool
history
[-il
]
[pool
]
...-
Displays the command history of the specified pools or all pools if no pool
is specified.
-i- Displays internally logged ZFS events in addition to user initiated
events.
-l- Displays log records in long format, which in addition to standard
format includes, the user name, the hostname, and the zone in which
the operation was performed.
zpool
import
[-d
dir | -c
cachefile
]
[-D
]-
Lists pools available to import. If the
-d option is not specified, this
command searches for devices in
“/dev”. The
-d option can be specified multiple
times, and all directories are searched. If the device appears to be part
of an exported pool, this command displays a summary of the pool with the
name of the pool, a numeric identifier, as well as the
vdev layout and current health of the device for
each device or file. Destroyed pools, pools that were previously destroyed
with the “zpool
destroy” command, are not listed
unless the -D option is specified.
The numeric identifier is unique, and can be used instead of the pool name
when multiple exported pools of the same name are available.
-c
cachefile- Reads configuration from the given
cachefile that was created with the
“cachefile” pool property.
This cachefile is used instead of
searching for devices.
-d
dir- Searches for devices or files in dir.
The
-d option can be specified
multiple times.
-D- Lists destroyed pools only.
zpool
import
[-o
mntopts
]
[-o
property=value
]
...
[-d
dir | -c
cachefile
]
[-D
]
[-f
]
[-m
]
[-N
]
[-R
root
]
[]
-a-
Imports all pools found in the search directories. Identical to the previous
command, except that all pools with a sufficient number of devices
available are imported. Destroyed pools, pools that were previously
destroyed with the “
zpool
destroy” command, will not be
imported unless the -D option is
specified.
-o
mntopts- Comma-separated list of mount options to use when mounting datasets
within the pool. See
zfs(8)
for a description of dataset properties and mount options.
-o
property=value- Sets the specified property on the imported pool. See the
“Properties”
section for more information on the available pool properties.
-c
cachefile- Reads configuration from the given
cachefile that was created with the
“cachefile” pool property.
This cachefile is used instead of
searching for devices.
-d
dir- Searches for devices or files in dir.
The
-d option can be specified
multiple times. This option is incompatible with the
-c option.
-D- Imports destroyed pools only. The
-f option is also required.
-f- Forces import, even if the pool appears to be potentially active.
-m- Allows a pool to import when there is a missing log device. Recent
transactions can be lost because the log device will be
discarded.
-N- Import the pool without mounting any file systems.
-R
root- Sets the “cachefile”
property to “
none”
and the “altroot” property
to “root”
-F- Recovery mode for a non-importable pool. Attempt to return the pool to
an importable state by discarding the last few transactions. Not all
damaged pools can be recovered by using this option. If successful,
the data from the discarded transactions is irretrievably lost. This
option is ignored if the pool is importable or already imported.
-n- Used with the
-F recovery option.
Determines whether a non-importable pool can be made importable again,
but does not actually perform the pool recovery. For more details
about pool recovery mode, see the
-F option, above.
-a- Searches for and imports all pools found.
zpool
import
[-o
mntopts
]
[-o
property=value
]
...
[-d
dir | -c
cachefile
]
[-D
]
[-f
]
[-m
]
[-N
]
[-R
root
]
[-t
]
[]
pool | id
[newpool
]-
Imports a specific pool. A pool can be identified by its name or the numeric
identifier. If newpool is specified, the
pool is imported using the name newpool.
Otherwise, it is imported with the same name as its exported name.
If a device is removed from a system without running
“
zpool
export” first, the device
appears as potentially active. It cannot be determined if this was a
failed export, or whether the device is really in use from another host.
To import a pool in this state, the -f
option is required.
-o
mntopts- Comma-separated list of mount options to use when mounting datasets
within the pool. See
zfs(8)
for a description of dataset properties and mount options.
-o
property=value- Sets the specified property on the imported pool. See the
“Properties”
section for more information on the available pool properties.
-c
cachefile- Reads configuration from the given
cachefile that was created with the
“cachefile” pool property.
This cachefile is used instead of
searching for devices.
-d
dir- Searches for devices or files in dir.
The
-d option can be specified
multiple times. This option is incompatible with the
-c option.
-D- Imports destroyed pools only. The
-f option is also required.
-f- Forces import, even if the pool appears to be potentially active.
-m- Allows a pool to import when there is a missing log device. Recent
transactions can be lost because the log device will be
discarded.
-N- Import the pool without mounting any file systems.
-R
root- Equivalent to “
-o
cachefile=none,altroot=root”
-t- Used with newpool. Specifies that
newpool is temporary. Temporary pool
names last until export. Ensures that the original pool name will be
used in all label updates and therefore is retained upon export. Will
also set cachefile property to
none when not explicitly specified.
-F- Recovery mode for a non-importable pool. Attempt to return the pool to
an importable state by discarding the last few transactions. Not all
damaged pools can be recovered by using this option. If successful,
the data from the discarded transactions is irretrievably lost. This
option is ignored if the pool is importable or already imported.
-n- Used with the
-F recovery option.
Determines whether a non-importable pool can be made importable again,
but does not actually perform the pool recovery. For more details
about pool recovery mode, see the
-F option, above.
--rewind-to-checkpoint- Rewinds pool to the checkpointed state. Once the pool is imported with
this flag there is no way to undo the rewind. All changes and data
that were written after the checkpoint are lost! The only exception is
when the readonly mounting option is
enabled. In this case, the checkpointed state of the pool is opened
and an administrator can see how the pool would look like if they were
to fully rewind.
zpool
initialize
[-cs
]
pool
[device...
]- Begins initializing by writing to all unallocated regions on the specified
devices, or all eligible devices in the pool if no individual devices are
specified. Only leaf data or log devices may be initialized.
-c,
--cancel- Cancel initializing on the specified devices, or all eligible devices
if none are specified. If one or more target devices are invalid or
are not currently being initialized, the command will fail and no
cancellation will occur on any device.
-s
--suspend- Suspend initializing on the specified devices, or all eligible devices
if none are specified. If one or more target devices are invalid or
are not currently being initialized, the command will fail and no
suspension will occur on any device. Initializing can then be resumed
by running
zpool
initialize with no flags on the
relevant target devices.
zpool
iostat
[-T
d|u
]
[-v
]
[pool
]
...
[]-
Displays I/O statistics for the given pools. When given an interval, the
statistics are printed every interval
seconds until Ctrl-C is pressed. If no
pools are specified, statistics for every
pool in the system is shown. If count is
specified, the command exits after count
reports are printed.
-T
d|u- Print a timestamp.
Use modifier
d for standard date
format. See
date(1).
Use modifier u for unixtime (equals
“date +%s”).
-v- Verbose statistics. Reports usage statistics for individual
vdevs within the pool, in addition to the
pool-wide statistics.
zpool
labelclear
[-f
]
device-
Removes ZFS label information from the specified
device. The
device must not be part of an active pool
configuration.
-f- Treat exported or foreign devices as inactive.
zpool
list
[-Hpv
]
[]
[-T
d|u
]
[pool
]
...
[]-
Lists the given pools along with a health status and space usage. If no
pools are specified, all pools in the
system are listed.
When given an interval, the output is printed every
interval seconds until
Ctrl-C is pressed. If
count is specified, the command exits
after count reports are printed.
-T
d|u- Print a timestamp.
Use modifier
d for standard date
format. See
date(1).
Use modifier u for unixtime (equals
“date +%s”).
-H- Scripted mode. Do not display headers, and separate fields by a single
tab instead of arbitrary space.
-p- Display numbers in parsable (exact) values.
-v- Verbose statistics. Reports usage statistics for individual
vdevs within the pool, in addition to the
pool-wide statistics.
-o
property[,...
]- Comma-separated list of properties to display. See the
“Properties”
section for a list of valid properties. The default list is
name, size,
used,
available,
checkpoint,
expandsize,
fragmentation,
capacity,
dedupratio,
health,
altroot.
-T
d|u- Print a timestamp.
Use modifier
d for standard date
format. See
date(1).
Use modifier u for unixtime (equals
“date +%s”).
zpool
offline
[-t
]
pool device ...-
Takes the specified physical device offline. While the
device is offline, no attempt is made to
read or write to the device.
-t- Temporary. Upon reboot, the specified physical device reverts to its
previous state.
zpool
online
[-e
]
pool device ...-
Brings the specified physical device online.
This command is not applicable to spares or cache devices.
-e- Expand the device to use all available space. If the device is part of
a mirror or raidz then all devices must be
expanded before the new space will become available to the pool.
zpool
reguid
pool-
Generates a new unique identifier for the pool. You must ensure that all
devices in this pool are online and healthy before performing this
action.
zpool
remove
[-np
]
pool device ...-
Removes the specified device from the pool. This command currently only
supports removing hot spares, cache, log devices and mirrored top-level
vdevs (mirror of leaf devices); but not raidz.
Removing a top-level vdev reduces the total amount of space in the storage
pool. The specified device will be evacuated by copying all allocated
space from it to the other devices in the pool. In this case, the
zpool
remove command initiates the removal
and returns, while the evacuation continues in the background. The removal
progress can be monitored with zpool
status. This feature must be enabled to
be used, see
zpool-features(5)
A mirrored top-level device (log or data) can be removed by specifying the
top-level mirror for the same. Non-log devices or data devices that are
part of a mirrored configuration can be removed using the
“zpool
detach” command.
-n- Do not actually perform the removal ("no-op"). Instead,
print the estimated amount of memory that will be used by the mapping
table after the removal completes. This is nonzero only for top-level
vdevs.
-p- Used in conjunction with the
-n
flag, displays numbers as parsable (exact) values.
zpool
remove
-s
pool-
Stops and cancels an in-progress removal of a top-level vdev.
zpool
reopen
pool-
Reopen all the vdevs associated with the pool.
zpool
replace
[-f
]
pool device
[new_device
]-
Replaces old_device with
new_device. This is equivalent to
attaching new_device, waiting for it to
resilver, and then detaching old_device.
The size of new_device must be greater than
or equal to the minimum size of all the devices in a mirror or
raidz configuration.
new_device is required if the pool is not
redundant. If new_device is not
specified, it defaults to old_device.
This form of replacement is useful after an existing disk has failed and
has been physically replaced. In this case, the new disk may have the same
/dev path as the old device, even
though it is actually a different disk. ZFS recognizes this.
-f- Forces use of new_device, even if its
appears to be in use. Not all devices can be overridden in this
manner.
zpool
scrub
[-s |
-p
] pool
...-
Begins a scrub or resumes a paused scrub. The scrub examines all data in the
specified pools to verify that it checksums correctly. For replicated
(mirror or raidz) devices, ZFS automatically repairs any damage discovered
during the scrub. The
zpool
status command reports the progress of
the scrub and summarizes the results of the scrub upon completion.
Scrubbing and resilvering are very similar operations. The difference is
that resilvering only examines data that ZFS knows to be out of date (for
example, when attaching a new device to a mirror or replacing an existing
device), whereas scrubbing examines all data to discover silent errors due
to hardware faults or disk failure.
Because scrubbing and resilvering are I/O-intensive operations, ZFS only
allows one at a time. If a scrub is paused, the
zpool
scrub resumes it. If a resilver is in
progress, ZFS does not allow a scrub to be started until the resilver
completes.
-s- Stop scrubbing.
-p- Pause scrubbing. Scrub pause state and progress are periodically
synced to disk. If the system is restarted or pool is exported during
a paused scrub, even after import, scrub will remain paused until it
is resumed. Once resumed the scrub will pick up from the place where
it was last checkpointed to disk. To resume a paused scrub issue
zpool
scrub again.
zpool
set
property=value
pool-
Sets the given property on the specified pool. See the
“Properties”
section for more information on what properties can be set and acceptable
values.
zpool
split
[-n
]
[-R
altroot
]
[-o
mntopts
]
[-o
property=value
]
pool newpool
[device ...
]-
Splits off one disk from each mirrored top-level
vdev in a pool and creates a new pool from the
split-off disks. The original pool must be made up of one or more mirrors
and must not be in the process of resilvering. The
split subcommand chooses the last
device in each mirror vdev unless overridden by a
device specification on the command line.
When using a device argument,
split includes the specified device(s)
in a new pool and, should any devices remain unspecified, assigns the last
device in each mirror vdev to that pool, as it
does normally. If you are uncertain about the outcome of a
split command, use the
-n ("dry-run") option to
ensure your command will have the effect you intend.
-R
altroot- Automatically import the newly created pool after splitting, using the
specified altroot parameter for the
new pool's alternate root. See the
altroot description in the
“Properties”
section, above.
-n- Displays the configuration that would be created without actually
splitting the pool. The actual pool split could still fail due to
insufficient privileges or device status.
-o
mntopts- Comma-separated list of mount options to use when mounting datasets
within the pool. See
zfs(8)
for a description of dataset properties and mount options. Valid only
in conjunction with the
-R
option.
-o
property=value- Sets the specified property on the new pool. See the
“Properties”
section, above, for more information on the available pool
properties.
zpool
status
[-vx
]
[-T
d|u
]
[pool
]
...
[]-
Displays the detailed health status for the given pools. If no
pool is specified, then the status of
each pool in the system is displayed. For more information on pool and
device health, see the
“Device
Failure and Recovery” section.
When given an interval, the output is printed every
interval seconds until
Ctrl-C is pressed. If
count is specified, the command exits
after count reports are printed.
If a scrub or resilver is in progress, this command reports the percentage
done and the estimated time to completion. Both of these are only
approximate, because the amount of data in the pool and the other
workloads on the system can change.
-x- Only display status for pools that are exhibiting errors or are
otherwise unavailable. Warnings about pools not using the latest
on-disk format, having non-native block size or disabled features will
not be included.
-v- Displays verbose data error information, printing out a complete list
of all data errors since the last complete pool scrub.
-T
d|u- Print a timestamp.
Use modifier
d for standard date
format. See
date(1).
Use modifier u for unixtime (equals
“date +%s”).
zpool
upgrade
[-v
]-
Displays pools which do not have all supported features enabled and pools
formatted using a legacy ZFS version number. These pools can continue to
be used, but some features may not be available. Use
zpool
upgrade
-a to enable all features on all pools.
-v- Displays legacy ZFS versions supported by the current software. See
zpool-features(7)
for a description of feature flags features supported by the current
software.
zpool
upgrade
[-V
version
]
-a | pool
...-
Enables all supported features on the given pool. Once this is done, the
pool will no longer be accessible on systems that do not support feature
flags. See
zpool-features(7)
for details on compatibility with systems that support feature flags, but
do not support all features enabled on the pool.
-a- Enables all supported features on all pools.
-V
version- Upgrade to the specified legacy version. If the
-V flag is specified, no features
will be enabled on the pool. This option can only be used to increase
version number up to the last supported legacy version number.
The following exit values are returned:
- 0
- Successful completion.
- 1
- An error occurred.
- 2
- Invalid command line options were specified.
- Example 1 Creating a RAID-Z
Storage Pool
-
The following command creates a pool with a single
raidz root vdev that
consists of six disks.
# zpool create tank raidz da0 da1 da2 da3 da4 da5
- Example 2 Creating a
Mirrored Storage Pool
-
The following command creates a pool with two mirrors, where each mirror
contains two disks.
# zpool create tank mirror da0 da1 mirror da2 da3
- Example 3 Creating a
ZFS Storage Pool by Using Partitions
-
The following command creates an unmirrored pool using two GPT partitions.
# zpool create tank da0p3 da1p3
- Example 4 Creating a
ZFS Storage Pool by Using Files
-
The following command creates an unmirrored pool using files. While not
recommended, a pool based on files can be useful for experimental
purposes.
# zpool create tank /path/to/file/a /path/to/file/b
- Example 5 Adding a Mirror to
a ZFS Storage Pool
-
The following command adds two mirrored disks to the pool
tank, assuming the pool is already made up of
two-way mirrors. The additional space is immediately available to any
datasets within the pool.
# zpool add tank mirror da2 da3
- Example 6 Listing
Available ZFS Storage Pools
-
The following command lists all available pools on the system.
# zpool list
NAME SIZE ALLOC FREE FRAG EXPANDSZ CAP DEDUP HEALTH ALTROOT
pool 2.70T 473G 2.24T 33% - 17% 1.00x ONLINE -
test 1.98G 89.5K 1.98G 48% - 0% 1.00x ONLINE -
- Example 7 Listing All
Properties for a Pool
-
The following command lists all the properties for a pool.
# zpool get all pool
pool size 2.70T -
pool capacity 17% -
pool altroot - default
pool health ONLINE -
pool guid 2501120270416322443 default
pool version 28 default
pool bootfs pool/root local
pool delegation on default
pool autoreplace off default
pool cachefile - default
pool failmode wait default
pool listsnapshots off default
pool autoexpand off default
pool dedupditto 0 default
pool dedupratio 1.00x -
pool free 2.24T -
pool allocated 473G -
pool readonly off -
- Example 8 Destroying
a ZFS Storage Pool
-
The following command destroys the pool
“tank” and any datasets
contained within.
- Example 9 Exporting a
ZFS Storage Pool
-
The following command exports the devices in pool
tank so that they can be relocated or later
imported.
- Example 10 Importing
a ZFS Storage Pool
-
The following command displays available pools, and then imports the pool
“tank” for use on the system.
The results from this command are similar to the following:
# zpool import
pool: tank
id: 15451357997522795478
state: ONLINE
action: The pool can be imported using its name or numeric identifier.
config:
tank ONLINE
mirror ONLINE
da0 ONLINE
da1 ONLINE
- Example 11 Upgrading All ZFS Storage Pools to
the Current Version
-
The following command upgrades all ZFS Storage pools to the current version
of the software.
# zpool upgrade -a
This system is currently running ZFS pool version 28.
- Example 12 Managing Hot
Spares
-
The following command creates a new pool with an available hot spare:
# zpool create tank mirror da0 da1 spare da2
If one of the disks were to fail, the pool would be reduced to the degraded
state. The failed device can be replaced using the following command:
# zpool replace tank da0 da2
Once the data has been resilvered, the spare is automatically removed and is
made available should another device fails. The hot spare can be
permanently removed from the pool using the following command:
- Example 13 Creating a ZFS Pool with Mirrored
Separate Intent Logs
-
The following command creates a ZFS storage pool consisting of two, two-way
mirrors and mirrored log devices:
# zpool create pool mirror da0 da1 mirror da2 da3 log mirror da4 da5
- Example 14 Adding Cache
Devices to a ZFS Pool
-
The following command adds two disks for use as cache devices to a ZFS
storage pool:
# zpool add pool cache da2 da3
Once added, the cache devices gradually fill with content from main memory.
Depending on the size of your cache devices, it could take over an hour
for them to fill. Capacity and reads can be monitored using the
iostat subcommand as follows:
- Example 15 Displaying expanded space on a
device
-
The following command dipslays the detailed information for the
data pool. This pool is comprised of a single
raidz vdev where one of its devices increased
its capacity by 10GB. In this example, the pool will not be able to
utilized this extra capacity until all the devices under the
raidz vdev have been expanded.
# zpool list -v data
NAME SIZE ALLOC FREE FRAG EXPANDSZ CAP DEDUP HEALTH ALTROOT
data 23.9G 14.6G 9.30G 48% - 61% 1.00x ONLINE -
raidz1 23.9G 14.6G 9.30G 48% -
ada0 - - - - -
ada1 - - - - 10G
ada2 - - - - -
- Example 16 Removing a Mirrored top-level (Log
or Data) Device
-
The following commands remove the mirrored log device
mirror-2 and mirrored top-level data device
mirror-1.
Given this configuration:
pool: tank
state: ONLINE
scrub: none requested
config:
NAME STATE READ WRITE CKSUM
tank ONLINE 0 0 0
mirror-0 ONLINE 0 0 0
da0 ONLINE 0 0 0
da1 ONLINE 0 0 0
mirror-1 ONLINE 0 0 0
da2 ONLINE 0 0 0
da3 ONLINE 0 0 0
logs
mirror-2 ONLINE 0 0 0
da4 ONLINE 0 0 0
da5 ONLINE 0 0 0
The command to remove the mirrored log mirror-2
is:
# zpool remove tank mirror-2
The command to remove the mirrored data
mirror-1 is:
# zpool remove tank mirror-1
- Example 17 Recovering a Faulted ZFS Pool
-
If a pool is faulted but recoverable, a message indicating this state is
provided by “
zpool
status” if the pool was cached
(see the -c
cachefile argument above), or as part of
the error output from a failed
“zpool
import” of the pool.
Recover a cached pool with the
“zpool
clear” command:
# zpool clear -F data
Pool data returned to its state as of Tue Sep 08 13:23:35 2009.
Discarded approximately 29 seconds of transactions.
If the pool configuration was not cached, use
“zpool
import” with the recovery mode
flag:
# zpool import -F data
Pool data returned to its state as of Tue Sep 08 13:23:35 2009.
Discarded approximately 29 seconds of transactions.
zpool-features(7),
zfs(8),
zfsd(8)
This manual page is a
mdoc(7)
reimplementation of the OpenSolaris manual page
zpool(1M), modified and customized for
FreeBSD and licensed under the Common Development and
Distribution License (CDDL).
The
mdoc(7)
implementation of this manual page was initially written by
Martin Matuska
⟨mm@FreeBSD.org⟩.
Visit the GSP FreeBSD Man Page Interface.