[LU-9206] DNE - allow partial access to striped dir if one of the MDTs is unavailable Created: 13/Mar/17  Updated: 06/Jan/22  Resolved: 06/Jan/22

Status: Resolved
Project: Lustre
Component/s: None
Affects Version/s: None
Fix Version/s: Lustre 2.15.0

Type: Improvement Priority: Minor
Reporter: Sarah Liu Assignee: Lai Siyao
Resolution: Fixed Votes: 0
Labels: LMR, dne3

Issue Links:
Duplicate
is duplicated by LU-9284 striped directory should be able to b... Resolved
Related
is related to LU-12310 MDT Device-level Replication/Mirroring Open
Rank (Obsolete): 9223372036854775807

 Description   

Hello,

Current for stripe dir, if 1 MDT is damaged, the whole dir cannot be accessed. We would like to change/improve the implementation to allow access to partial of the stripe dir on undamaged MDTs.

use case:
DIR1 cross 4 MDTs, one of the MDT (Not MDT0) is damaged
1. Create DIR1 as a striped dir cross all 4 MDTs
2. Umount MDT1
3. Data on other undamaged MDT should be accessible

 Comments   
Comment by Andreas Dilger [ 07/Apr/20 ]

Lai,
I think this problem of accessing a directory with offline stripes is already fixed? Is there already a test for this? If yes, then this should be linked to the patch that fixed the problem.

If not, then test could do something like:

  • create striped directory
  • create 100 files in it
  • "lfs getstripe -m" all entries to determine which MDT each file is on
  • take one MDT offline
  • "ls -l" directory to check that entries for online MDTs are still available
  • verify that none of the offline entries are listed
  • verify that "ls -l' returns an error at the end
  • take MDT online
  • verify that all files are accessible again.
Comment by Gerrit Updater [ 22/Nov/21 ]

"Lai Siyao <lai.siyao@whamcloud.com>" uploaded a new patch: https://review.whamcloud.com/45631
Subject: LU-9206 llite: access striped directory with missing stripe
Project: fs/lustre-release
Branch: master
Current Patch Set: 1
Commit: 8982e179d90eed2baa8845468d317c2f10c43ad2

Comment by Gerrit Updater [ 06/Jan/22 ]

"Oleg Drokin <green@whamcloud.com>" merged in patch https://review.whamcloud.com/45631/
Subject: LU-9206 llite: access striped directory with missing stripe
Project: fs/lustre-release
Branch: master
Current Patch Set:
Commit: c0fa6f7a10d1162f8d49d40ab4f5aba80e72157e

Comment by Peter Jones [ 06/Jan/22 ]

Landed for 2.15

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