Date: Fri, 26 May 2017 11:54:42 +0000 (UTC) From: Andriy Gapon <avg@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-vendor@freebsd.org Subject: svn commit: r318936 - vendor/illumos/dist/man/man1m Message-ID: <201705261154.v4QBsguB089025@repo.freebsd.org>
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Author: avg Date: Fri May 26 11:54:42 2017 New Revision: 318936 URL: https://svnweb.freebsd.org/changeset/base/318936 Log: 4465 zpool(1M) is able to offline cache vdevs despite what man page says 5659 in the manual page for zpool(1M), one misuse of the word 'zpool' to describe a pool illumos/illumos-gate@c8323d4323a565676ba44883bfeb289d9ed8813e https://github.com/illumos/illumos-gate/commit/c8323d4323a565676ba44883bfeb289d9ed8813e https://www.illumos.org/issues/4465 zpool(1M) is able to offline cache vdevs despite man page saying that it isn't: 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. This command is not applicable to spares or cache devices. altair:root:~# zpool create testoff c9t67d0 cache c9t71d0 altair:root:~# zpool status testoff pool: testoff state: ONLINE scan: none requested config: NAME STATE READ WRITE CKSUM testoff ONLINE 0 0 0 c9t67d0 ONLINE 0 0 0 cache c9t71d0 ONLINE 0 0 0 errors: No known data errors altair:root:~# zpool offline testoff c9t71d0 altair:root:~# zpool status testoff pool: testoff state: ONLINE status: One or more devices has been taken offline by the administrator. Sufficient replicas exist for the pool to continue functioning in a degraded state. action: Online the device using 'zpool online' or replace the device with 'zpool replace'. scan: none requested https://www.illumos.org/issues/5659 At https://github.com/illumos/illumos-gate/blob/master/usr/src/man/man1m/ zpool.1m#L931 Do not add a disk that is currently configured as a quorum device to a zpool. – should be: Do not add a disk that is currently configured as a quorum device to a pool. Reviewed by: Matthew Ahrens <mahrens@delphix.com> Approved by: Hans Rosenfeld <rosenfeld@grumpf.hope-2000.org> Author: Yuri Pankov <yuri.pankov@nexenta.com> Modified: vendor/illumos/dist/man/man1m/zpool.1m Modified: vendor/illumos/dist/man/man1m/zpool.1m ============================================================================== --- vendor/illumos/dist/man/man1m/zpool.1m Fri May 26 11:49:42 2017 (r318935) +++ vendor/illumos/dist/man/man1m/zpool.1m Fri May 26 11:54:42 2017 (r318936) @@ -1,747 +1,535 @@ -'\" te +.\" +.\" CDDL HEADER START +.\" +.\" The contents of this file are subject to the terms of the +.\" Common Development and Distribution License (the "License"). +.\" You may not use this file except in compliance with the License. +.\" +.\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE +.\" or http://www.opensolaris.org/os/licensing. +.\" See the License for the specific language governing permissions +.\" and limitations under the License. +.\" +.\" When distributing Covered Code, include this CDDL HEADER in each +.\" file and include the License file at usr/src/OPENSOLARIS.LICENSE. +.\" If applicable, add the following below this CDDL HEADER, with the +.\" fields enclosed by brackets "[]" replaced with your own identifying +.\" information: Portions Copyright [yyyy] [name of copyright owner] +.\" +.\" CDDL HEADER END +.\" +.\" .\" Copyright (c) 2007, Sun Microsystems, Inc. All Rights Reserved. -.\" Copyright 2011, Nexenta Systems, Inc. All Rights Reserved. .\" Copyright (c) 2013 by Delphix. All rights reserved. -.\" The contents of this file are subject to the terms of the Common Development -.\" and Distribution License (the "License"). You may not use this file except -.\" in compliance with the License. You can obtain a copy of the license at -.\" usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing. +.\" Copyright 2016 Nexenta Systems, Inc. .\" -.\" See the License for the specific language governing permissions and -.\" limitations under the License. When distributing Covered Code, include this -.\" CDDL HEADER in each file and include the License file at -.\" usr/src/OPENSOLARIS.LICENSE. If applicable, add the following below this -.\" CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your -.\" own identifying information: -.\" Portions Copyright [yyyy] [name of copyright owner] -.TH ZPOOL 1M "Mar 6, 2014" -.SH NAME -zpool \- configures ZFS storage pools -.SH SYNOPSIS -.LP -.nf -\fBzpool\fR [\fB-?\fR] -.fi - -.LP -.nf -\fBzpool add\fR [\fB-fn\fR] \fIpool\fR \fIvdev\fR ... -.fi - -.LP -.nf -\fBzpool attach\fR [\fB-f\fR] \fIpool\fR \fIdevice\fR \fInew_device\fR -.fi - -.LP -.nf -\fBzpool clear\fR \fIpool\fR [\fIdevice\fR] -.fi - -.LP -.nf -\fBzpool create\fR [\fB-fnd\fR] [\fB-o\fR \fIproperty=value\fR] ... [\fB-O\fR \fIfile-system-property=value\fR] - ... [\fB-m\fR \fImountpoint\fR] [\fB-R\fR \fIroot\fR] \fIpool\fR \fIvdev\fR ... -.fi - -.LP -.nf -\fBzpool destroy\fR [\fB-f\fR] \fIpool\fR -.fi - -.LP -.nf -\fBzpool detach\fR \fIpool\fR \fIdevice\fR -.fi - -.LP -.nf -\fBzpool export\fR [\fB-f\fR] \fIpool\fR ... -.fi - -.LP -.nf -\fBzpool get\fR [\fB-Hp\fR] [\fB-o \fR\fIfield\fR[,...]] "\fIall\fR" | \fIproperty\fR[,...] \fIpool\fR ... -.fi - -.LP -.nf -\fBzpool history\fR [\fB-il\fR] [\fIpool\fR] ... -.fi - -.LP -.nf -\fBzpool import\fR [\fB-d\fR \fIdir\fR] [\fB-D\fR] -.fi - -.LP -.nf -\fBzpool import\fR [\fB-o \fImntopts\fR\fR] [\fB-o\fR \fIproperty=value\fR] ... [\fB-d\fR \fIdir\fR | \fB-c\fR \fIcachefile\fR] - [\fB-D\fR] [\fB-f\fR] [\fB-m\fR] [\fB-N\fR] [\fB-R\fR \fIroot\fR] [\fB-F\fR [\fB-n\fR]] \fB-a\fR -.fi - -.LP -.nf -\fBzpool import\fR [\fB-o \fImntopts\fR\fR] [\fB-o\fR \fIproperty=value\fR] ... [\fB-d\fR \fIdir\fR | \fB-c\fR \fIcachefile\fR] - [\fB-D\fR] [\fB-f\fR] [\fB-m\fR] [\fB-R\fR \fIroot\fR] [\fB-F\fR [\fB-n\fR]] \fIpool\fR |\fIid\fR [\fInewpool\fR] -.fi - -.LP -.nf -\fBzpool iostat\fR [\fB-T\fR \fBu\fR | \fBd\fR ] [\fB-v\fR] [\fIpool\fR] ... [\fIinterval\fR[\fIcount\fR]] -.fi - -.LP -.nf -\fBzpool list\fR [\fB-T\fR \fBu\fR | \fBd\fR ] [\fB-Hpv\fR] [\fB-o\fR \fIproperty\fR[,...]] [\fIpool\fR] ... [\fIinterval\fR[\fIcount\fR]] -.fi - -.LP -.nf -\fBzpool offline\fR [\fB-t\fR] \fIpool\fR \fIdevice\fR ... -.fi - -.LP -.nf -\fBzpool online\fR \fIpool\fR \fIdevice\fR ... -.fi - -.LP -.nf -\fBzpool reguid\fR \fIpool\fR -.fi - -.LP -.nf -\fBzpool reopen\fR \fIpool\fR -.fi - -.LP -.nf -\fBzpool remove\fR \fIpool\fR \fIdevice\fR ... -.fi - -.LP -.nf -\fBzpool replace\fR [\fB-f\fR] \fIpool\fR \fIdevice\fR [\fInew_device\fR] -.fi - -.LP -.nf -\fBzpool scrub\fR [\fB-s\fR] \fIpool\fR ... -.fi - -.LP -.nf -\fBzpool set\fR \fIproperty\fR=\fIvalue\fR \fIpool\fR -.fi - -.LP -.nf -\fBzpool status\fR [\fB-xvD\fR] [\fB-T\fR \fBu\fR | \fBd\fR ] [\fIpool\fR] ... [\fIinterval\fR [\fIcount\fR]] -.fi - -.LP -.nf -\fBzpool upgrade\fR -.fi - -.LP -.nf -\fBzpool upgrade\fR \fB-v\fR -.fi - -.LP -.nf -\fBzpool upgrade\fR [\fB-V\fR \fIversion\fR] \fB-a\fR | \fIpool\fR ... -.fi - -.SH DESCRIPTION -.sp -.LP -The \fBzpool\fR command configures \fBZFS\fR storage pools. A storage pool is a -collection of devices that provides physical storage and data replication for -\fBZFS\fR datasets. -.sp -.LP -All datasets within a storage pool share the same space. See \fBzfs\fR(1M) for -information on managing datasets. -.SS "Virtual Devices (\fBvdev\fRs)" -.sp -.LP +.Dd February 15, 2016 +.Dt ZPOOL 1M +.Os +.Sh NAME +.Nm zpool +.Nd configure ZFS storage pools +.Sh SYNOPSIS +.Nm +.Fl \? +.Nm +.Cm add +.Op Fl fn +.Ar pool vdev Ns ... +.Nm +.Cm attach +.Op Fl f +.Ar pool device new_device +.Nm +.Cm clear +.Ar pool +.Op Ar device +.Nm +.Cm create +.Op Fl dfn +.Op Fl m Ar mountpoint +.Oo Fl o Ar property Ns = Ns Ar value Oc Ns ... +.Oo Fl O Ar file-system-property Ns = Ns Ar value Oc Ns ... +.Op Fl R Ar root +.Ar pool vdev Ns ... +.Nm +.Cm destroy +.Op Fl f +.Ar pool +.Nm +.Cm detach +.Ar pool device +.Nm +.Cm export +.Op Fl f +.Ar pool Ns ... +.Nm +.Cm get +.Op Fl Hp +.Op Fl o Ar field Ns Oo , Ns Ar field Oc Ns ... +.Sy all Ns | Ns Ar property Ns Oo , Ns Ar property Oc Ns ... +.Ar pool Ns ... +.Nm +.Cm history +.Op Fl il +.Oo Ar pool Oc Ns ... +.Nm +.Cm import +.Op Fl D +.Op Fl d Ar dir +.Nm +.Cm import +.Fl a +.Op Fl DfmN +.Op Fl F Op Fl n +.Op Fl c Ar cachefile Ns | Ns Fl d Ar dir +.Op Fl o Ar mntopts +.Oo Fl o Ar property Ns = Ns Ar value Oc Ns ... +.Op Fl R Ar root +.Nm +.Cm import +.Op Fl Dfm +.Op Fl F Op Fl n +.Op Fl c Ar cachefile Ns | Ns Fl d Ar dir +.Op Fl o Ar mntopts +.Oo Fl o Ar property Ns = Ns Ar value Oc Ns ... +.Op Fl R Ar root +.Ar pool Ns | Ns Ar id +.Op Ar newpool +.Nm +.Cm iostat +.Op Fl v +.Op Fl T Sy u Ns | Ns Sy d +.Oo Ar pool Oc Ns ... +.Op Ar interval Op Ar count +.Nm +.Cm list +.Op Fl Hpv +.Op Fl o Ar property Ns Oo , Ns Ar property Oc Ns ... +.Op Fl T Sy u Ns | Ns Sy d +.Oo Ar pool Oc Ns ... +.Op Ar interval Op Ar count +.Nm +.Cm offline +.Op Fl t +.Ar pool Ar device Ns ... +.Nm +.Cm online +.Op Fl e +.Ar pool Ar device Ns ... +.Nm +.Cm reguid +.Ar pool +.Nm +.Cm reopen +.Ar pool +.Nm +.Cm remove +.Ar pool Ar device Ns ... +.Nm +.Cm replace +.Op Fl f +.Ar pool Ar device Op Ar new_device +.Nm +.Cm scrub +.Op Fl s +.Ar pool Ns ... +.Nm +.Cm set +.Ar property Ns = Ns Ar value +.Ar pool +.Nm +.Cm status +.Op Fl Dvx +.Op Fl T Sy u Ns | Ns Sy d +.Oo Ar pool Oc Ns ... +.Op Ar interval Op Ar count +.Nm +.Cm upgrade +.Nm +.Cm upgrade +.Fl v +.Nm +.Cm upgrade +.Op Fl V Ar version +.Fl a Ns | Ns Ar pool Ns ... +.Sh DESCRIPTION +The +.Nm +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 +.Xr zfs 1M +for information on managing datasets. +.Ss 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: -.sp -.ne 2 -.na -\fB\fBdisk\fR\fR -.ad -.RS 10n -A block device, typically located under \fB/dev/dsk\fR. \fBZFS\fR 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, \fBZFS\fR automatically labels the disk, if necessary. -.RE - -.sp -.ne 2 -.na -\fB\fBfile\fR\fR -.ad -.RS 10n +.Bl -tag -width Ds +.It Sy disk +A block device, typically located under +.Pa /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 +.Po the relative portion of the path under +.Pa /dev/dsk +.Pc . +A whole disk can be specified by omitting the slice or partition designation. +For example, +.Pa c0t0d0 +is equivalent to +.Pa /dev/dsk/c0t0d0s2 . +When given a whole disk, ZFS automatically labels the disk, if necessary. +.It Sy 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. -.RE - -.sp -.ne 2 -.na -\fB\fBmirror\fR\fR -.ad -.RS 10n +.It Sy mirror A mirror of two or more devices. Data is replicated in an identical fashion -across all components of a mirror. A mirror with \fIN\fR disks of size \fIX\fR -can hold \fIX\fR bytes and can withstand (\fIN-1\fR) devices failing before -data integrity is compromised. -.RE - -.sp -.ne 2 -.na -\fB\fBraidz\fR\fR -.ad -.br -.na -\fB\fBraidz1\fR\fR -.ad -.br -.na -\fB\fBraidz2\fR\fR -.ad -.br -.na -\fB\fBraidz3\fR\fR -.ad -.RS 10n -A variation on \fBRAID-5\fR that allows for better distribution of parity and -eliminates the "\fBRAID-5\fR write hole" (in which data and parity become -inconsistent after a power loss). Data and parity is striped across all disks -within a \fBraidz\fR group. -.sp -A \fBraidz\fR group can have single-, double- , or triple parity, meaning that -the \fBraidz\fR group can sustain one, two, or three failures, respectively, -without losing any data. The \fBraidz1\fR \fBvdev\fR type specifies a -single-parity \fBraidz\fR group; the \fBraidz2\fR \fBvdev\fR type specifies a -double-parity \fBraidz\fR group; and the \fBraidz3\fR \fBvdev\fR type specifies -a triple-parity \fBraidz\fR group. The \fBraidz\fR \fBvdev\fR type is an alias -for \fBraidz1\fR. -.sp -A \fBraidz\fR group with \fIN\fR disks of size \fIX\fR with \fIP\fR parity -disks can hold approximately (\fIN-P\fR)*\fIX\fR bytes and can withstand -\fIP\fR device(s) failing before data integrity is compromised. The minimum -number of devices in a \fBraidz\fR group is one more than the number of parity -disks. The recommended number is between 3 and 9 to help increase performance. -.RE - -.sp -.ne 2 -.na -\fB\fBspare\fR\fR -.ad -.RS 10n -A special pseudo-\fBvdev\fR which keeps track of available hot spares for a -pool. For more information, see the "Hot Spares" section. -.RE - -.sp -.ne 2 -.na -\fB\fBlog\fR\fR -.ad -.RS 10n -A separate-intent log device. If more than one log device is specified, then +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. +.It Sy raidz , raidz1 , raidz2 , raidz3 +A variation on RAID-5 that allows for better distribution of parity and +eliminates the RAID-5 +.Qq write hole +.Pq in which data and parity become inconsistent after a power loss . +Data and parity is striped across all disks within a raidz group. +.Pp +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 +.Sy raidz1 +vdev type specifies a single-parity raidz group; the +.Sy raidz2 +vdev type specifies a double-parity raidz group; and the +.Sy raidz3 +vdev type specifies a triple-parity raidz group. The +.Sy raidz +vdev type is an alias for +.Sy raidz1 . +.Pp +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. +.It Sy spare +A special pseudo-vdev which keeps track of available hot spares for a pool. For +more information, see the +.Sx Hot Spares +section. +.It Sy 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, -\fBraidz\fR \fBvdev\fR types are not supported for the intent log. For more -information, see the "Intent Log" section. -.RE - -.sp -.ne 2 -.na -\fB\fBcache\fR\fR -.ad -.RS 10n +raidz vdev types are not supported for the intent log. For more information, +see the +.Sx Intent Log +section. +.It Sy cache A device used to cache storage pool data. A cache device cannot be cannot be -configured as a mirror or \fBraidz\fR group. For more information, see the -"Cache Devices" section. -.RE - -.sp -.LP -Virtual devices cannot be nested, so a mirror or \fBraidz\fR virtual device can -only contain files or disks. Mirrors of mirrors (or other combinations) are not -allowed. -.sp -.LP +configured as a mirror or raidz group. For more information, see the +.Sx Cache Devices +section. +.El +.Pp +Virtual devices cannot be nested, so a mirror or raidz virtual device can only +contain files or disks. Mirrors of mirrors +.Pq or other combinations +are not allowed. +.Pp 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, -\fBZFS\fR automatically places data on the newly available devices. -.sp -.LP +.Po known as +.Qq root vdevs +.Pc . +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. +.Pp 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: -.sp -.in +2 -.nf -# \fBzpool create mypool mirror c0t0d0 c0t1d0 mirror c1t0d0 c1t1d0\fR -.fi -.in -2 -.sp - -.SS "Device Failure and Recovery" -.sp -.LP -\fBZFS\fR supports a rich set of mechanisms for handling device failure and -data corruption. All metadata and data is checksummed, and \fBZFS\fR -automatically repairs bad data from a good copy when corruption is detected. -.sp -.LP +whitespace. The keywords +.Sy mirror +and +.Sy 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: +.Bd -literal +# zpool create mypool mirror c0t0d0 c0t1d0 mirror c1t0d0 c1t1d0 +.Ed +.Ss 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. +.Pp In order to take advantage of these features, a pool must make use of some form -of redundancy, using either mirrored or \fBraidz\fR groups. While \fBZFS\fR -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. -.sp -.LP +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. +.Pp 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. -.sp -.LP -The health of the top-level vdev, such as mirror or \fBraidz\fR device, is +.Pp +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: -.sp -.ne 2 -.na -\fB\fBDEGRADED\fR\fR -.ad -.RS 12n +.Bl -tag -width "DEGRADED" +.It Sy 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. -.sp +.Pp 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: -.RS +4 -.TP -.ie t \(bu -.el o +.Bl -bullet +.It The number of checksum errors exceeds acceptable levels and the device is -degraded as an indication that something may be wrong. \fBZFS\fR continues to -use the device as necessary. -.RE -.RS +4 -.TP -.ie t \(bu -.el o +degraded as an indication that something may be wrong. ZFS continues to use the +device as necessary. +.It 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. -.RE -.RE - -.sp -.ne 2 -.na -\fB\fBFAULTED\fR\fR -.ad -.RS 12n +.El +.It Sy 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. -.sp +.Pp One or more component devices is in the faulted state, and insufficient replicas exist to continue functioning. The underlying conditions are as follows: -.RS +4 -.TP -.ie t \(bu -.el o +.Bl -bullet +.It The device could be opened, but the contents did not match expected values. -.RE -.RS +4 -.TP -.ie t \(bu -.el o +.It The number of I/O errors exceeds acceptable levels and the device is faulted to prevent further use of the device. -.RE -.RE - -.sp -.ne 2 -.na -\fB\fBOFFLINE\fR\fR -.ad -.RS 12n -The device was explicitly taken offline by the "\fBzpool offline\fR" command. -.RE - -.sp -.ne 2 -.na -\fB\fBONLINE\fR\fR -.ad -.RS 12n +.El +.It Sy OFFLINE +The device was explicitly taken offline by the +.Nm zpool Cm offline +command. +.It Sy ONLINE The device is online and functioning. -.RE - -.sp -.ne 2 -.na -\fB\fBREMOVED\fR\fR -.ad -.RS 12n +.It Sy 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. -.RE - -.sp -.ne 2 -.na -\fB\fBUNAVAIL\fR\fR -.ad -.RS 12n +.It Sy 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. -.RE - -.sp -.LP -If a device is removed and later re-attached to the system, \fBZFS\fR attempts +.El +.Pp +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. -.SS "Hot Spares" -.sp -.LP -\fBZFS\fR 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" \fBvdev\fR with any number of devices. For example, -.sp -.in +2 -.nf +.Ss Hot Spares +ZFS allows devices to be associated with pools as +.Qq 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 +.Sy spare +vdev with any number of devices. For example, +.Bd -literal # zpool create pool mirror c0d0 c1d0 spare c2d0 c3d0 -.fi -.in -2 -.sp - -.sp -.LP -Spares can be shared across multiple pools, and can be added with the "\fBzpool -add\fR" command and removed with the "\fBzpool remove\fR" command. Once a spare -replacement is initiated, a new "spare" \fBvdev\fR 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. -.sp -.LP +.Ed +.Pp +Spares can be shared across multiple pools, and can be added with the +.Nm zpool Cm add +command and removed with the +.Nm zpool Cm remove +command. Once a spare replacement is initiated, a new +.Sy 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. +.Pp 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. -.sp -.LP +.Pp 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. -.sp -.LP +.Pp Spares cannot replace log devices. -.SS "Intent Log" -.sp -.LP -The \fBZFS\fR Intent Log (\fBZIL\fR) satisfies \fBPOSIX\fR requirements for -synchronous transactions. For instance, databases often require their -transactions to be on stable storage devices when returning from a system call. -\fBNFS\fR and other applications can also use \fBfsync\fR() 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 \fBNVRAM\fR or a dedicated disk. For example: -.sp -.in +2 -.nf -\fB# zpool create pool c0d0 c1d0 log c2d0\fR -.fi -.in -2 -.sp - -.sp -.LP +.Ss 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 +.Xr fsync 3C +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: +.Bd -literal +# zpool create pool c0d0 c1d0 log c2d0 +.Ed +.Pp Multiple log devices can also be specified, and they can be mirrored. See the -EXAMPLES section for an example of mirroring multiple log devices. -.sp -.LP +.Sx EXAMPLES +section for an example of mirroring multiple log devices. +.Pp 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. -.SS "Cache Devices" -.sp -.LP -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 +.Ss Cache Devices +Devices can be added to a storage pool as +.Qq 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. -.sp -.LP -To create a pool with cache devices, specify a "cache" \fBvdev\fR with any -number of devices. For example: -.sp -.in +2 -.nf -\fB# zpool create pool c0d0 c1d0 cache c2d0 c3d0\fR -.fi -.in -2 -.sp - -.sp -.LP -Cache devices cannot be mirrored or part of a \fBraidz\fR configuration. If a -read error is encountered on a cache device, that read \fBI/O\fR is reissued to -the original storage pool device, which might be part of a mirrored or -\fBraidz\fR configuration. -.sp -.LP +.Pp +To create a pool with cache devices, specify a +.Sy cache +vdev with any number of devices. For example: +.Bd -literal +# zpool create pool c0d0 c1d0 cache c2d0 c3d0 +.Ed +.Pp +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. +.Pp The content of the cache devices is considered volatile, as is the case with other system caches. -.SS "Properties" -.sp -.LP +.Ss 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: -.sp -.ne 2 -.na -\fB\fBavailable\fR\fR -.ad -.RS 20n +the pool. +.Pp +The following are read-only properties: +.Bl -tag -width Ds +.It Sy available Amount of storage available within the pool. This property can also be referred -to by its shortened column name, "avail". -.RE - -.sp -.ne 2 -.na -\fB\fBcapacity\fR\fR -.ad -.RS 20n +to by its shortened column name, +.Sy avail . +.It Sy capacity Percentage of pool space used. This property can also be referred to by its -shortened column name, "cap". -.RE - -.sp -.ne 2 -.na -\fB\fBexpandsize\fR\fR -.ad -.RS 20n +shortened column name, +.Sy cap . +.It Sy 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. -.RE - -.sp -.ne 2 -.na -\fB\fBfragmentation\fR\fR -.ad -.RS 20n +.Po e.g, using +.Nm zpool Cm online Fl e +.Pc . +This space occurs when a LUN is dynamically expanded. +.It Sy fragmentation The amount of fragmentation in the pool. -.RE - -.sp -.ne 2 -.na -\fB\fBfree\fR\fR -.ad -.RS 20n +.It Sy free The amount of free space available in the pool. -.RE - -.sp -.ne 2 -.na -\fB\fBfreeing\fR\fR -.ad -.RS 20n +.It Sy freeing After a file system or snapshot is destroyed, the space it was using is -returned to the pool asynchronously. \fB\fBfreeing\fR\fR is the amount of -space remaining to be reclaimed. Over time \fB\fBfreeing\fR\fR will decrease -while \fB\fBfree\fR\fR increases. -.RE - -.sp -.ne 2 -.na -\fB\fBhealth\fR\fR -.ad -.RS 20n -The current health of the pool. Health can be "\fBONLINE\fR", "\fBDEGRADED\fR", -"\fBFAULTED\fR", " \fBOFFLINE\fR", "\fBREMOVED\fR", or "\fBUNAVAIL\fR". -.RE - -.sp -.ne 2 -.na -\fB\fBguid\fR\fR -.ad -.RS 20n +returned to the pool asynchronously. +.Sy freeing +is the amount of space remaining to be reclaimed. Over time +.Sy freeing +will decrease while +.Sy free +increases. +.It Sy health +The current health of the pool. Health can be one of +.Sy ONLINE , DEGRADED , FAULTED , OFFLINE, REMOVED , UNAVAIL . +.It Sy guid A unique identifier for the pool. -.RE - -.sp -.ne 2 -.na *** DIFF OUTPUT TRUNCATED AT 1000 LINES ***
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