table of contents
zpool(8) | System Administration Commands | zpool(8) |
NAME¶
zpool - configures ZFS storage poolsSYNOPSIS¶
zpool [-?]
zpool add [-fn] [-o property=value] pool vdev ...
zpool attach [-f] [-o property=value] pool device new_device
zpool clear [-F [-n]] pool [device]
zpool create [-fn] [-o property=value] ... [-O file-system-property=value] ... [ -m mountpoint] [-R root] pool vdev ...
zpool destroy [-f] pool
zpool detach pool device
zpool export [-f] pool ...
zpool get "all" | property[,...] pool ...
zpool history [-il] [pool] ...
zpool import [-d dir] [-D]
zpool import [-o mntopts] [-o property=value] ... [-d dir | -c cachefile] [ -D] [-f] [-R root] [-F [-n]] -a
zpool import [-o mntopts] [-o property=value] ... [-d dir | -c cachefile] [ -D] [-f] [-R root] [-F [-n]] pool |id [newpool]
zpool iostat [-T u | d ] [-v] [pool] ... [interval[count]]
zpool list [-H] [-o property[,...]] [pool] ...
zpool offline [-t] pool device ...
zpool online pool device ...
zpool remove pool device ...
zpool replace [-f] pool device [new_device]
zpool scrub [-s] pool ...
zpool set property=value pool
zpool split [-R altroot] [-n] [-o mntopts] [-o property=value] pool newpool [device ...]
zpool status [-xv] [pool] ...
zpool upgrade
zpool upgrade -v
zpool upgrade [-V version] -a | pool ...
DESCRIPTION¶
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(1M) for information on managing datasets.Virtual Devices ( vdevs)¶
A "virtual device" describes a single device or a collection of devices organized according to certain performance and fault characteristics. The following virtual devices are supported: diskA block device, typically located under /dev/dsk.
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, or it can be a shorthand name (the relative portion of the path under
"/dev/dsk"). A whole disk can be specified by omitting the slice or
partition designation. For example, "c0t0d0" is equivalent to
"/dev/dsk/c0t0d0s2". 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 as 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
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 c0t0d0 c0t1d0 mirror c1t0d0 c1t1d0
Device Failure and Recovery¶
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: DEGRADEDOne 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:
FAULTED
- o
- 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.
- o
- 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.
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:
OFFLINE
- o
- The device could be opened, but the contents did not match expected values.
- o
- The number of I/O errors exceeds acceptable levels and the device is faulted to prevent further use of the device.
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 re-attached 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.
Hot Spares¶
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 c0d0 c1d0 spare c2d0 c3d0
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.
Intent Log¶
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() 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 c0d0 c1d0 log c2d0
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, and imported and exported as part of the larger pool. Mirrored log devices can be removed by specifying the top-level mirror for the log.
Cache Devices¶
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 c0d0 c1d0 cache c2d0 c3d0
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.
Processes¶
Each imported pool has an associated process, named zpool-poolname. The threads in this process are the pool's I/O processing threads, which handle the compression, checksumming, and other tasks for all I/O associated with the pool. This process exists to provides visibility into the CPU utilization of the system's storage pools. The existence of this process is an unstable interface.Properties¶
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: allocAmount 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".
dedupratio
The deduplication ratio specified for a pool, expressed
as a multiplier. Deduplication can be turned on by entering the command:
The default value is off. dedupratio is expressed as a single decimal number. 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.
free
# zfs set dedup=on dataset
The default value is off. dedupratio is expressed as a single decimal number. 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.
Number of blocks within the pool that are not
allocated.
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.
These 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(1M) command takes into account, but the
zpool 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:
ashift
Pool sector size exponent, to the power of 2 (internally
referred to as "ashift"). I/O operations will be aligned to the
specified size boundaries. Additionally, the minimum (disk) write size will be
set to the specified size, so this represents a space vs. performance
trade-off. The typical case for setting this property is when performance is
important and the underlying disks use 4KiB sectors but report 512B sectors to
the OS (for compatibility reasons); in that case, set ashift=12 (which
is 1<<12 = 4096). Since most large disks have had 4K sectors since 2011,
ZFS defaults to ashift=12 for all disks larger than 512 GB.
For optimal performance, the pool sector size should be greater than or equal to
the sector size of the underlying disks. Since the property cannot be changed
after pool creation, if in a given pool, you ever want to use drives
that report 4KiB sectors, you must set ashift=12 at pool
creation time.
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 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.
Multiple pools can share the same cache file. Because the kernel destroys and
recreates this file when pools are added and removed, care should be taken
when attempting to access this file. When the last pool using a
cachefile is exported or destroyed, the file is removed.
delegation=on | off
Controls whether a non-privileged user is granted access
based on the dataset permissions defined on the dataset. See zfs(1M)
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
listsnaps=on | off
Blocks all I/O access to the pool until the device
connectivity is recovered and the errors are cleared. A pool remains in the
wait state until the device issue is resolved. 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.
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. This
property can be any number between 1 and the current version reported by
" zpool upgrade -v".
Subcommands¶
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] [-o property=value]
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
zpool attach [-f] [-o property=value]
pool device new_device
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 adding the vdevs. The actual pool creation can still fail due
to insufficient privileges or device sharing.
-o property=value
Sets the given pool properties. See the
"Properties" section for a list of valid properties that can be set.
The only property supported at the moment is "ashift".
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.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
zpool clear [-F [-n]] pool [device]
...
Forces use of new_device, even if its appears to
be in use. Not all devices can be overridden in this manner.
-o property=value
Sets the given pool properties. See the
"Properties" section for a list of valid properties that can be set.
The only property supported at the moment is "ashift".
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
zpool create [-fn] [-o property=value] ...
[-O file-system-property=value] ... [-m
mountpoint] [ -R root] pool vdev ...
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.
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.
-f
[-O file-system-property=value] ...
zpool destroy [-f] pool
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.
-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
Sets the given file system properties in the root file
system of the pool. See the "Properties" section of zfs(1M)
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(1M).
Destroys the given pool, freeing up any devices for other
use. This command tries to unmount any active datasets before destroying the
pool.
-f
zpool detach pool device
Forces any active datasets contained within the pool to
be unmounted.
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
zpool get "all" | property[,...]
pool ...
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.
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:
See the "Properties" section for more information on the available pool properties.
zpool history [-il] [pool] ...
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.
Displays the command history of the specified pools or
all pools if no pool is specified.
-i
zpool import [-d dir | -c cachefile]
[-D]
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.
Lists pools available to import. If the -d option
is not specified, this command searches for devices in "/dev/dsk".
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
zpool import [-o mntopts] [ -o
property= value] ... [-d dir | -c
cachefile] [ -D] [-f] [-R root] [-F
[ -n]] -a
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.
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
zpool import [-o mntopts] [ -o
property= value] ... [-d dir | -c
cachefile] [ -D] [-f] [-R root] [-F
[ -n]] pool | id [newpool]
Comma-separated list of mount options to use when
mounting datasets within the pool. See zfs(1M) 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.
-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.
-a
Searches for and imports all pools found.
-R root
Sets the "cachefile" property to
"none" and the "altroot" property to
"root".
-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.
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
zpool iostat [-T u | d] [-v]
[pool] ... [ interval[count]]
Comma-separated list of mount options to use when
mounting datasets within the pool. See zfs(1M) 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 pool. The -f option is also
required.
-f
Forces import, even if the pool appears to be potentially
active.
-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.
-R root
Sets the "cachefile" property to
"none" and the "altroot" property to
"root".
-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.
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 u | d
zpool list [-H] [-o props[,...]]
[pool] ...
Display a time stamp.
Specify u for a printed representation of the internal representation of
time. See time(2). Specify d for standard date format. See
date(1).
-v
Verbose statistics. Reports usage statistics for
individual vdevs within the pool, in addition to the pool-wide
statistics.
Lists the given pools along with a health status and
space usage. When given no arguments, all pools in the system are listed.
-H
zpool offline [-t] pool device ...
Scripted mode. Do not display headers, and separate
fields by a single tab instead of arbitrary space.
-o props
Comma-separated list of properties to display. See the
"Properties" section for a list of valid properties. The default
list is name, size, allocated, free,
capacity, health, altroot.
Takes the specified physical device offline. While the
device is offline, no attempt is made to read or write to the device.
This command is not applicable to spares or cache devices.
-t
zpool online [-e] pool device...
Temporary. Upon reboot, the specified physical device
reverts to its previous state.
Brings the specified physical device online.
This command is not applicable to spares or cache devices.
-e
zpool remove pool device ...
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.
Removes the specified device from the pool. This command
currently only supports removing hot spares, cache, and log devices. A
mirrored log device can be removed by specifying the top-level mirror for the
log. Non-log devices that are part of a mirrored configuration can be removed
using the zpool detach command. Non-redundant and raidz devices
cannot be removed from a pool.
zpool replace [-f] pool old_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/dsk path as the old
device, even though it is actually a different disk. ZFS recognizes
this.
-f
zpool scrub [-s] pool ...
Forces use of new_device, even if its appears to
be in use. Not all devices can be overridden in this manner.
Begins a 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 already in progress, the
" zpool scrub" command terminates it and starts a new scrub.
If a resilver is in progress, ZFS does not allow a scrub to be started
until the resilver completes.
-s
zpool set property=value pool
Stop scrubbing.
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 [-R altroot] [-n] [-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
zpool status [-xv] [pool] ...
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(1M) 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.
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.
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
zpool upgrade
Only display status for pools that are exhibiting errors
or are otherwise unavailable.
-v
Displays verbose data error information, printing out a
complete list of all data errors since the last complete pool scrub.
Displays all pools formatted using a different ZFS
on-disk version. Older versions can continue to be used, but some features may
not be available. These pools can be upgraded using " zpool upgrade
-a". Pools that are formatted with a more recent version are also
displayed, although these pools will be inaccessible on the system.
zpool upgrade -v
Displays ZFS versions supported by the current
software. The current ZFS versions and all previous supported versions
are displayed, along with an explanation of the features provided with each
version.
zpool upgrade [-V version] -a | pool
...
Upgrades the given pool to the latest on-disk version.
Once this is done, the pool will no longer be accessible on systems running
older versions of the software.
-a
Upgrades all pools.
-V version
Upgrade to the specified version. If the -V flag
is not specified, the pool is upgraded to the most recent version. This option
can only be used to increase the version number, and only up to the most
recent version supported by this software.
EXAMPLES¶
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 c0t0d0 c0t1d0 c0t2d0 c0t3d0 c0t4d0 c0t5d0
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 c0t0d0 c0t1d0 mirror c0t2d0 c0t3d0
Example 3 Creating a ZFS Storage Pool by Using Slices The following command creates an unmirrored pool using two disk slices.
# zpool create tank /dev/dsk/c0t0d0s1 c0t1d0s4
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 c1t0d0 c1t1d0
Example 6 Listing Available ZFS Storage Pools The following command lists all available pools on the system.
# zpool list NAME SIZE ALLOC FREE CAP DEDUP HEALTH ALTROOT pool 136G 109M 136G 0% 3.00x ONLINE - rpool 67.5G 12.6G 54.9G 18% 1.01x ONLINE -
Example 7 Listing All Properties for a Pool The following command lists all the properties for a pool.
% zpool get all pool NAME PROPERTY VALUE SOURCE pool size 136G - pool capacity 0% - pool altroot - default pool health ONLINE - pool guid 15697759092019394988 default pool version 21 default pool bootfs - default pool delegation on default pool autoreplace off default pool cachefile - default pool failmode wait default pool listsnapshots off default pool autoexpand off default pool dedupratio 3.00x - pool free 136G - pool allocated 109M -
Example 8 Destroying a ZFS Storage Pool The following command destroys the pool " tank" and any datasets contained within.
# zpool destroy -f tank
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.
# zpool export tank
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: 7678868315469843843 state: ONLINE action: The pool can be imported using its name or numeric identifier. config: tank ONLINE mirror-0 ONLINE c1t2d0 ONLINE c1t3d0 ONLINE # zpool import tank
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 19. All pools are formatted using this version.
Example 12 Managing Hot Spares The following command creates a new pool with an available hot spare:
# zpool create tank mirror c0t0d0 c0t1d0 spare c0t2d0
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 c0t0d0 c0t3d0
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:
# zpool remove tank c0t2d0
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 c0d0 c1d0 mirror c2d0 c3d0 log mirror \ c4d0 c5d0
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 c2d0 c3d0
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 option as follows:
# zpool iostat -v pool 5
Example 15 Removing a Mirrored Log Device The following command removes the mirrored log device mirror-2. 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 c6t0d0 ONLINE 0 0 0 c6t1d0 ONLINE 0 0 0 mirror-1 ONLINE 0 0 0 c6t2d0 ONLINE 0 0 0 c6t3d0 ONLINE 0 0 0 logs mirror-2 ONLINE 0 0 0 c4t0d0 ONLINE 0 0 0 c4t1d0 ONLINE 0 0 0
The command to remove the mirrored log mirror-2 is:
# zpool remove tank mirror-2
Example 16 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 cachefile 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.
EXIT STATUS¶
The following exit values are returned: 0Successful completion.
1
An error occurred.
2
Invalid command line options were specified.
ATTRIBUTES¶
See attributes(5) for descriptions of the following attributes:ATTRIBUTE TYPE | ATTRIBUTE VALUE |
Availability | SUNWzfsu |
Interface Stability | Committed |
SEE ALSO¶
zfs(1M), attributes(5)4 Jan 2010 | SunOS 5.11 |