[LU-9206] DNE - allow partial access to striped dir if one of the MDTs is unavailable

• Type: Improvement
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.15.0
• Labels: LMR dne3
• Assignee: Lai Siyao
• Reporter: Sarah Liu

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

Issue Links

• is duplicated by: LU-9284 striped directory should be able to be accessed even if one stripe MDT is failed.
• is related to: LU-17818 LMR: Lustre Metadata Redundancy
• is related to: LU-12310 MDT Device-level Replication/Mirroring