OpenZFS 8166 - zpool scrub thinks it repaired offline device #6103
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Reviewed by: George Wilson [email protected] If we do a scrub while a leaf device is offline (via "zpool offline"), we will inadvertently clear the DTL (dirty time log) of the offline device, even though it is still damaged. When the device comes back online, we will incompletely resilver it, thinking that the scrub repaired blocks written before the scrub was started. The incomplete resilver can lead to data loss if there is a subsequent failure of a different leaf device. The fix is to never clear the DTL of offline devices. Note that if a device is onlined while a scrub is in progress, the scrub will be restarted. The problem can be worked around by running "zpool scrub" after "zpool online". Closes openzfs#5806
|
@ahrens, thanks for your PR! By analyzing the history of the files in this pull request, we identified @behlendorf, @grwilson and @tonyhutter to be potential reviewers. |
behlendorf
approved these changes
May 9, 2017
tonyhutter
pushed a commit
to tonyhutter/zfs
that referenced
this pull request
May 26, 2017
Authored by: Matthew Ahrens <[email protected]> Reviewed by: George Wilson <[email protected]> Reviewed-by: loli10K <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Ported-by: Matthew Ahrens <[email protected]> If we do a scrub while a leaf device is offline (via "zpool offline"), we will inadvertently clear the DTL (dirty time log) of the offline device, even though it is still damaged. When the device comes back online, we will incompletely resilver it, thinking that the scrub repaired blocks written before the scrub was started. The incomplete resilver can lead to data loss if there is a subsequent failure of a different leaf device. The fix is to never clear the DTL of offline devices. Note that if a device is onlined while a scrub is in progress, the scrub will be restarted. The problem can be worked around by running "zpool scrub" after "zpool online". OpenZFS-issue: https://www.illumos.org/issues/8166 OpenZFS-commit: openzfs/openzfs#372 Closes openzfs#5806 Closes openzfs#6103
tonyhutter
pushed a commit
that referenced
this pull request
Jun 9, 2017
Authored by: Matthew Ahrens <[email protected]> Reviewed by: George Wilson <[email protected]> Reviewed-by: loli10K <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Ported-by: Matthew Ahrens <[email protected]> If we do a scrub while a leaf device is offline (via "zpool offline"), we will inadvertently clear the DTL (dirty time log) of the offline device, even though it is still damaged. When the device comes back online, we will incompletely resilver it, thinking that the scrub repaired blocks written before the scrub was started. The incomplete resilver can lead to data loss if there is a subsequent failure of a different leaf device. The fix is to never clear the DTL of offline devices. Note that if a device is onlined while a scrub is in progress, the scrub will be restarted. The problem can be worked around by running "zpool scrub" after "zpool online". OpenZFS-issue: https://www.illumos.org/issues/8166 OpenZFS-commit: openzfs/openzfs#372 Closes #5806 Closes #6103
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Description
Reviewed by: George Wilson [email protected]
If we do a scrub while a leaf device is offline (via "zpool offline"),
we will inadvertently clear the DTL (dirty time log) of the offline
device, even though it is still damaged. When the device comes back
online, we will incompletely resilver it, thinking that the scrub
repaired blocks written before the scrub was started. The incomplete
resilver can lead to data loss if there is a subsequent failure of a
different leaf device.
The fix is to never clear the DTL of offline devices. Note that if a
device is onlined while a scrub is in progress, the scrub will be
restarted.
The problem can be worked around by running "zpool scrub" after
"zpool online".
Closes #5806
Motivation and Context
Issue #5806
See also openzfs/openzfs#372
How Has This Been Tested?
Script in #5806, zfs test suite, ztest.
Types of changes
Checklist:
Signed-off-by.