[LU-5550] LFSCK 5: Migrate the name entry from one MDT to another MDT if the name hash does not match the striped directory

• Type: Bug
• Resolution: Unresolved
• Priority: Minor
• Affects Version/s: Lustre 2.7.0
• Labels: dne3 lfsck
• Severity: 3
• Assignee: nasf (Inactive)
• Reporter: nasf (Inactive)

Description

The namespace LFSCK will check whether the name hash for the name entry under the slave of striped directory matches such shard or not. If not, the LFSCK should migrate the name entry from current MDT to the right MDT. This should be done with async commit supported from DNE2 to avoid lost the name entry or duplicate the name entry and some other recovery troubles.

Issue Links

• is related to: LU-4684 DNE3: allow migrating DNE striped directory

Comments

[Olaf Faaland]

If crash+bug resulted in the situation described, would current lfsck detect and report the issue, even if it cannot yet repair it?

[Andreas Dilger]

This would essentially allow migrating to or from a striped directory, or changing the directory striping arbitrarily, so long as it was clear what the "goal" directory count was, and the directory was marked with LMV_HASH_FLAG_MIGRATION so that clients knew to query all of the directory shards when doing a lookup.