2 .\" Copyright (c) 2016 Allan Jude
3 .\" All rights reserved.
5 .\" Redistribution and use in source and binary forms, with or without
6 .\" modification, are permitted provided that the following conditions
8 .\" 1. Redistributions of source code must retain the above copyright
9 .\" notice, this list of conditions and the following disclaimer.
10 .\" 2. Redistributions in binary form must reproduce the above copyright
11 .\" notice, this list of conditions and the following disclaimer in the
12 .\" documentation and/or other materials provided with the distribution.
14 .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 .\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 .Nd ZFS fault management daemon
39 attempts to resolve ZFS faults that the kernel can't resolve by itself.
42 events, which are how the kernel notifies userland of events such as I/O
43 errors and disk removals.
45 attempts to resolve these faults by activating or deactivating hot spares
46 and onlining offline vdevs.
48 The following options are available:
49 .Bl -tag -width indent
51 Run in the foreground instead of daemonizing.
54 System administrators never interact with
57 Instead, they control its behavior indirectly through zpool configuration.
58 There are two ways to influence
60 assigning hotspares and setting pool properties.
63 property has any effect.
69 will attempt to resolve the following types of fault:
72 When a leaf vdev disappears,
74 will activate any available hotspare.
76 When a new GEOM device appears,
78 will attempt to read its ZFS label, if any.
79 If it matches a previously removed vdev on an active pool,
82 Once resilvering completes, any active hotspare will detach automatically.
84 If the new device has no ZFS label but its physical path matches the
85 physical path of a previously removed vdev on an active pool, and that
86 pool has the autoreplace property set, then
88 will replace the missing vdev with the newly arrived device.
89 Once resilvering completes, any active hotspare will detach automatically.
90 .It vdev degrade or fault events
91 If a vdev becomes degraded or faulted,
93 will activate any available hotspare.
95 If a leaf vdev generates more than 50 I/O errors in a 60 second period, then
97 will mark that vdev as
99 ZFS will no longer issue any I/Os to it.
101 will activate a hotspare if one is available.
103 If a leaf vdev generates more than 50 checksum errors in a 60 second
106 will mark that vdev as
108 ZFS will still use it, but zfsd will activate a spare anyway.
110 If the system administrator adds a hotspare to a pool that is already degraded,
112 will activate the spare.
113 .It Resilver complete
115 will detach any hotspare once a permanent replacement finishes resilvering.
116 .It Physical path change
117 If the physical path of an existing disk changes,
119 will attempt to replace any missing disk with the same physical path,
120 if its pool's autoreplace property is set.
124 will log interesting events and its actions to syslog with facility
130 .Bl -tag -width a -compact
131 .It Pa /var/db/zfsd/cases
134 exits, it serializes any unresolved casefiles here,
135 then reads them back in when next it starts up.
146 was originally written by
147 .An Justin Gibbs Aq Mt gibbs@FreeBSD.org
149 .An Alan Somers Aq Mt asomers@FreeBSD.org
153 should be able to resume a pool that became suspended due to device
154 removals, if enough missing devices have returned.