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Feature #15069

MDS: multifs: enable two filesystems to point to same pools if one of them is marked damaged

Added by John Spray over 1 year ago. Updated 3 months ago.

Status:
Resolved
Priority:
Normal
Category:
multi-FS
Target version:
-
Start date:
03/11/2016
Due date:
% Done:

0%

Source:
other
Tags:
Backport:
Reviewed:
User Impact:
Affected Versions:
Release:
Component(FS):
Needs Doc:
No

Description

The 'damaged' flag on a filesystem prevents any MDS from being assigned a rank in that filesystem. While a filesystem is damaged, we should allow another filesystem to be created that targets the same pools (or possibly only the same data pools?), so that that filesystem could be used for repair (http://tracker.ceph.com/issues/15068).

The typical workflow would be that we had an existing filesystem 'A' that used pools 'data' and 'metadata'. It got marked damaged, and the user decided to create a new filesystem 'B' that uses pools 'newmetadata' and 'data'. They would then use repair tools to regenerate metadata into 'newmetadata', while avoiding the need to do any copying of stuff in the data pool.

Once they were happy with the new situation, they could then remove the old damaged filesystem. If something went wrong with repair and their old filesystem was in a "better than nothing" state, they could also remove the new filesystem and start the old one up again.

Because the damaged flag will have this new purpose, we will also need a command for the user to explicity set it (currently they can unset it with 'repaired' but it's only set initially by request of an MDS).

History

#1 Updated by Greg Farnum about 1 year ago

  • Subject changed from multifs: enable two filesystems to point to same pools if one of them is marked damaged to MDS: multifs: enable two filesystems to point to same pools if one of them is marked damaged
  • Category changed from 47 to multi-FS

#2 Updated by Douglas Fuller about 1 year ago

  • Status changed from New to In Progress
  • Assignee set to Douglas Fuller

#3 Updated by Douglas Fuller 12 months ago

  • Status changed from In Progress to Need Review

#4 Updated by John Spray 3 months ago

  • Status changed from Need Review to Resolved

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