7a0c41d5d7
Add zfsd, which deals with hard drive faults in ZFS pools. It manages hotspares and replements in drive slots that publish physical paths. cddl/usr.sbin/zfsd Add zfsd(8) and its unit tests cddl/usr.sbin/Makefile Add zfsd to the build lib/libdevdctl A C++ library that helps devd clients process events lib/Makefile share/mk/bsd.libnames.mk share/mk/src.libnames.mk Add libdevdctl to the build. It's a private library, unusable by out-of-tree software. etc/defaults/rc.conf By default, set zfsd_enable to NO etc/mtree/BSD.include.dist Add a directory for libdevdctl's include files etc/mtree/BSD.tests.dist Add a directory for zfsd's unit tests etc/mtree/BSD.var.dist Add /var/db/zfsd/cases, where zfsd stores case files while it's shut down. etc/rc.d/Makefile etc/rc.d/zfsd Add zfsd's rc script sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev.c Fix the resource.fs.zfs.statechange message. It had a number of problems: It was only being emitted on a transition to the HEALTHY state. That made it impossible for zfsd to take actions based on drives getting sicker. It compared the new state to vdev_prevstate, which is the state that the vdev had the last time it was opened. That doesn't make sense, because a vdev can change state multiple times without being reopened. vdev_set_state contains logic that will change the device's new state based on various conditions. However, the statechange event was being posted _before_ that logic took effect. Now it's being posted after. Submitted by: gibbs, asomers, mav, allanjude Reviewed by: mav, delphij Relnotes: yes Sponsored by: Spectra Logic Corp, iX Systems Differential Revision: https://reviews.freebsd.org/D6564
158 lines
4.5 KiB
Groff
158 lines
4.5 KiB
Groff
.\"-
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.\" Copyright (c) 2016 Allan Jude
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd May 26, 2016
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.Dt ZFSD 8
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.Os
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.Sh NAME
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.Nm zfsd
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.Nd ZFS fault management daemon
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.Sh SYNOPSIS
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.Nm
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.Op Fl d
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.Sh DESCRIPTION
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.Nm
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attempts to resolve ZFS faults that the kernel can't resolve by itself.
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It listens to
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.Xr devctl 4
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events, which are how the kernel notifies userland of events such as I/O
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errors and disk removals.
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.Nm
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attempts to resolve these faults by activating or deactivating hot spares
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and onlining offline vdevs.
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.Pp
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The following options are available:
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.Bl -tag -width indent
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.It Fl d
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Run in the foreground instead of daemonizing.
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.El
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.Pp
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System administrators never interact with
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.Nm
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directly.
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Instead, they control its behavior indirectly through zpool configuration.
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There are two ways to influence
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.Nm :
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assigning hotspares and setting pool properties.
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Currently, only the
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.Em autoreplace
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property has any effect.
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See
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.Xr zpool 8
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for details.
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.Pp
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.Nm
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will attempt to resolve the following types of fault:
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.Bl -tag -width a
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.It device removal
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When a leaf vdev disappears,
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.Nm
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will activate any available hotspare.
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.It device arrival
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When a new GEOM device appears,
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.Nm
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will attempt to read its ZFS label, if any.
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If it matches a previously removed vdev on an active pool,
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.Nm
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will online it.
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Once resilvering completes, any active hotspare will detach automatically.
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.Pp
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If the new device has no ZFS label but its physical path matches the
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physical path of a previously removed vdev on an active pool, and that
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pool has the autoreplace property set, then
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.Nm
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will replace the missing vdev with the newly arrived device.
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Once resilvering completes, any active hotspare will detach automatically.
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.It vdev degrade or fault events
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If a vdev becomes degraded or faulted,
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.Nm
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will activate any available hotspare.
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.It I/O errors
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If a leaf vdev generates more than 50 I/O errors in a 60 second period, then
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.Nm
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will mark that vdev as
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.Em FAULTED .
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.Xr zfs 4
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will no longer issue any I/Os to it.
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.Nm
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will activate a hotspare if one is available.
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.It Checksum errors
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If a leaf vdev generates more than 50 checksum errors in a 60 second
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period, then
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.Nm
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will mark that vdev as
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.Em DEGRADED .
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.Xr zfs 4
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will still use it, but zfsd will activate a spare anyway.
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.It Spare addition
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If the system administrator adds a hotspare to a pool that is already degraded,
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.Nm
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will activate the spare.
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.It Resilver complete
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.Nm
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will detach any hotspare once a permanent replacement finishes resilvering.
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.It Physical path change
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If the physical path of an existing disk changes,
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.Nm
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will attempt to replace any missing disk with the same physical path,
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if its pool's autoreplace property is set.
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.El
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.Pp
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.Nm
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will log interesting events and its actions to syslog with facility
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.Em daemon
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and identity
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.Op zfsd .
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.El
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.Sh FILES
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.Bl -tag -width a -compact
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.It Pa /var/db/zfsd/cases
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When
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.Nm
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exits, it serializes any unresolved casefiles here,
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then reads them back in when next it starts up.
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.El
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.Sh SEE ALSO
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.Xr devctl 4 ,
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.Xr zfs 4 ,
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.Xr zpool 8
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.Sh HISTORY
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.Nm
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first appeared in
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.Fx 11.0 .
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.Sh AUTHORS
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.Nm
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was originally written by
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.An Justin Gibbs Aq Mt gibbs@FreeBSD.org
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and
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.An Alan Somers Aq Mt asomers@FreeBSD.org
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.Sh TODO
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In the future,
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.Nm
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should be able to resume a pool that became suspended due to device
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removals, if enough missing devices have returned.
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