zfsd
attempts to resolve ZFS faults that the kernel can't resolve by itself.
It listens to
devctl(4)
events, which are how the kernel notifies userland of events such as I/O
errors and disk removals.
zfsd
attempts to resolve these faults by activating or deactivating hot spares
and onlining offline vdevs.
The following options are available:
|
| -d
|
| |
Run in the foreground instead of daemonizing.
|
|
System administrators never interact with
zfsd
directly.
Instead, they control its behavior indirectly through zpool configuration.
There are two ways to influence
zfsd:
assigning hotspares and setting pool properties.
Currently, only the
autoreplace
property has any effect.
See
zpool(8)
for details.
zfsd
will attempt to resolve the following types of fault:
| device removal
|
| |
When a leaf vdev disappears,
zfsd
will activate any available hotspare.
|
| device arrival
|
| |
When a new GEOM device appears,
zfsd
will attempt to read its ZFS label, if any.
If it matches a previously removed vdev on an active pool,
zfsd
will online it.
Once resilvering completes, any active hotspare will detach automatically.
If the new device has no ZFS label but its physical path matches the
physical path of a previously removed vdev on an active pool, and that
pool has the autoreplace property set, then
zfsd
will replace the missing vdev with the newly arrived device.
Once resilvering completes, any active hotspare will detach automatically.
|
| vdev degrade or fault events
|
| |
If a vdev becomes degraded or faulted,
zfsd
will activate any available hotspare.
|
| I/O errors
|
| |
If a leaf vdev generates more than 50 I/O errors in a 60 second period, then
zfsd
will mark that vdev as
FAULTED.
ZFS will no longer issue any I/Os to it.
zfsd
will activate a hotspare if one is available.
|
| Checksum errors
|
| |
If a leaf vdev generates more than 50 checksum errors in a 60 second
period, then
zfsd
will mark that vdev as
DEGRADED.
ZFS will still use it, but zfsd will activate a spare anyway.
|
| Spare addition
|
| |
If the system administrator adds a hotspare to a pool that is already degraded,
zfsd
will activate the spare.
|
| Resilver complete
|
| |
zfsd
will detach any hotspare once a permanent replacement finishes resilvering.
|
| Physical path change
|
| |
If the physical path of an existing disk changes,
zfsd
will attempt to replace any missing disk with the same physical path,
if its pool's autoreplace property is set.
|
|
zfsd
will log interesting events and its actions to syslog with facility
daemon
and identity
[zfsd].
