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Bug #12774
closed
Resilver restarts unnecessarily when it encounters errors
Start date:
Due date:
% Done:
100%
Estimated time:
Difficulty:
Medium
Tags:
Gerrit CR:
External Bug:
Description
Port of two OpenZFS changes:
commit 41035a049643ff7083a6cb6cd43b8eb70a7d18a1
Author: John Poduska <jpoduska@datto.com>
Date: Wed May 13 13:54:27 2020 -0400
Resilver restarts unnecessarily when it encounters errors
When a resilver finishes, vdev_dtl_reassess is called to hopefully
excise DTL_MISSING (amongst other things). If there are errors during
the resilver, they are tracked in DTL_SCRUB, as spelled out in the
block comment in vdev.c. DTL_SCRUB is in-core only, so it can only
be used if the pool was online for the whole resilver. This state is
tracked with the spa_scrub_started flag, which only gets set when
the scan is initialized. Unfortunately, this flag gets cleared right
before vdev_dtl_reassess gets called, so if there are any errors
during the scan, DTL_MISSING will never get excised and the resilver
will just continually restart. This fix simply moves clearing that
flag until after the call to vdev_dtl_reasses.
In addition, if a pool is imported and already has scn_errors > 0,
this change will restart the resilver immediately instead of doing
the rest of the scan and then restarting it from the beginning. On
the other hand, if scn_errors == 0 at import, then no errors have
been encountered so far, so the spa_scrub_started flag can be safely
set.
A test has been added to verify that resilver does not restart when
relevant DTL's are available.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Paul Zuchowski <pzuchowski@datto.com>
Signed-off-by: John Poduska <jpoduska@datto.com>
Closes #10291
<pre>
And a smaller related change:
<pre>
commit 02638a30efb0e9800fdc8834d5b7ab66432db00a
Author: Tim Chase <tim@chase2k.com>
Date: Tue Mar 13 12:43:14 2018 -0500
Add zfs_scan_ignore_errors tunable
When it's set, a DTL range will be cleared even if its scan/scrub had
errors. This allows to work around resilver/scrub upon import when the
pool has errors.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tim Chase <tim@chase2k.com>
Closes #7293
</pre>
Updated by Jason King almost 3 years ago
To test, I ran the zfs test suite (which included a new test for this change). All of the expected tests pass, and all the failures were known issues with existing bugs.
Updated by Jason King almost 3 years ago
The original description goes into the details as to why, but to highlight the core behaviors:
Prior to this change, errors during a resilver can cause the resilver to never finish and continually restart (this fixes it).
Additionally, if a pool with errors is imported, it will immediately try a resilver instead finishing the scan.
Updated by Electric Monk almost 3 years ago
- Status changed from New to Closed
- % Done changed from 0 to 100
git commit 165c5c6fe7d6c7a95878c8a3aae7da65d1da1d90
commit 165c5c6fe7d6c7a95878c8a3aae7da65d1da1d90
Author: John Poduska <jpoduska@datto.com>
Date: 2020-05-22T19:16:38.000Z
12774 Resilver restarts unnecessarily when it encounters errors
Portions contributed by: Tim Chase <tim@chase2k.com>
Portions contributed by: Jason King <jason.king@joyent.com>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Paul Zuchowski <pzuchowski@datto.com>
Reviewed by: Toomas Soome <tsoome@me.com>
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