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.Dd August 9, 2019
.Dt ZPOOL-SCRUB 8
.Os Linux
.Sh NAME
.Nm zpool Ns Pf - Cm scrub
.Nd Begin a scrub or resume a paused scrub of a ZFS storage pool
.Sh SYNOPSIS
.Nm
.Cm scrub
.Op Fl s | Fl p
.Op Fl w
.Ar pool Ns ...
.Sh DESCRIPTION
.Bl -tag -width Ds
.It Xo
.Nm
.Cm scrub
.Op Fl s | Fl p
.Op Fl w
.Ar pool Ns ...
.Xc
Begins a scrub or resumes a paused scrub.
The scrub examines all data in the specified pools to verify that it checksums
correctly.
For replicated
.Pq mirror or raidz
devices, ZFS automatically repairs any damage discovered during the scrub.
The
.Nm zpool Cm status
command reports the progress of the scrub and summarizes the results of the
scrub upon completion.
.Pp
Scrubbing and resilvering are very similar operations.
The difference is that resilvering only examines data that ZFS knows to be out
of date
.Po
for example, when attaching a new device to a mirror or replacing an existing
device
.Pc ,
whereas scrubbing examines all data to discover silent errors due to hardware
faults or disk failure.
.Pp
Because scrubbing and resilvering are I/O-intensive operations, ZFS only allows
one at a time.
If a scrub is paused, the
.Nm zpool Cm scrub
resumes it.
If a resilver is in progress, ZFS does not allow a scrub to be started until the
resilver completes.
.Pp
Note that, due to changes in pool data on a live system, it is possible for
scrubs to progress slightly beyond 100% completion. During this period, no
completion time estimate will be provided.
.Bl -tag -width Ds
.It Fl s
Stop scrubbing.
.El
.Bl -tag -width Ds
.It Fl p
Pause scrubbing.
Scrub pause state and progress are periodically synced to disk.
If the system is restarted or pool is exported during a paused scrub,
even after import, scrub will remain paused until it is resumed.
Once resumed the scrub will pick up from the place where it was last
checkpointed to disk.
To resume a paused scrub issue
.Nm zpool Cm scrub
again.
.It Fl w
Wait until scrub has completed before returning.
.El
.El
.Sh SEE ALSO
.Xr zpool-iostat 8 ,
.Xr zpool-resilver 8 ,
.Xr zpool-status 8