Implement OI Scrub for ZFS (LU-7585)

[LU-10192] Agent entry for cross-MDTs reference Created: 02/Nov/17  Updated: 31/Aug/18  Resolved: 04/Jan/18

Status: Resolved
Project: Lustre
Component/s: None
Affects Version/s: None
Fix Version/s: Lustre 2.11.0

Type: Technical task Priority: Minor
Reporter: nasf (Inactive) Assignee: nasf (Inactive)
Resolution: Fixed Votes: 0
Labels: None

Issue Links:
Related
is related to LU-11306 Moving files from one MDT to another ... Resolved
is related to LU-10329 DNE3: REMOTE_PARENT_DIR scalability Open
Rank (Obsolete): 9223372036854775807

 Description   

In DNE environment, the object and its name entry may reside on different MDTs. Under such case, we will create an agent entry under backend REMOTE_PARENT_DIR directory on the MDT where the object resides. The agent entry references the object locally. If without the agent entry, related object will be invisible for MDT side file level backup restore by userspace tool, such as 'tar'.

ldiskfs supports agent entry. After migrated to ZFS, the agent entry will be on ZFS backend. ZFS needs to handle it to avoid dangling.

On the other hand, there may be a lot of corss-MDTs reference for regular file. That may make the single REMOTE_PARENT_DIR very fat as to quite slow for being operated. So it is preferred to optimised that with multiple REMOTE_PARENT_DIRs, may be per MDT per REMOTE_PARENT_DIR.



 Comments   
Comment by Gerrit Updater [ 08/Nov/17 ]

Fan Yong (fan.yong@intel.com) uploaded a new patch: https://review.whamcloud.com/29984
Subject: LU-10192 osd-ldiskfs: create agent entry for remote entry
Project: fs/lustre-release
Branch: master
Current Patch Set: 1
Commit: 2a4c25b6db3e68de8410010f5d812c99f5ac70c5

Comment by Gerrit Updater [ 08/Nov/17 ]

Fan Yong (fan.yong@intel.com) uploaded a new patch: https://review.whamcloud.com/29985
Subject: LU-10192 lfsck: verify agent entry
Project: fs/lustre-release
Branch: master
Current Patch Set: 1
Commit: 600e4251b33254b8fe54d592a8eb58472794bab0

Comment by nasf (Inactive) [ 08/Nov/17 ]

Another patch:
https://review.whamcloud.com/29617

Comment by Gerrit Updater [ 14/Nov/17 ]

Fan Yong (fan.yong@intel.com) uploaded a new patch: https://review.whamcloud.com/30075
Subject: LU-10192 test: debug patch for sanity-hsm test_406
Project: fs/lustre-release
Branch: master
Current Patch Set: 1
Commit: 3d9e1ecc1e7b65c7914e059a5d0a6948dae26f76

Comment by Gerrit Updater [ 22/Dec/17 ]

Oleg Drokin (oleg.drokin@intel.com) merged in patch https://review.whamcloud.com/29984/
Subject: LU-10192 osd-ldiskfs: create agent entry for remote entry
Project: fs/lustre-release
Branch: master
Current Patch Set:
Commit: 81a26d51b61646c067b27bd094ee2cf01ca13fdc

Comment by Gerrit Updater [ 22/Dec/17 ]

Oleg Drokin (oleg.drokin@intel.com) merged in patch https://review.whamcloud.com/29617/
Subject: LU-10192 osd-zfs: create agent entry for remote entry
Project: fs/lustre-release
Branch: master
Current Patch Set:
Commit: 5f3235b250cd952548344262db0d70d6134c66cb

Comment by Gerrit Updater [ 04/Jan/18 ]

Oleg Drokin (oleg.drokin@intel.com) merged in patch https://review.whamcloud.com/29985/
Subject: LU-10192 lfsck: verify agent entry
Project: fs/lustre-release
Branch: master
Current Patch Set:
Commit: 83ed9453f0cd89057edae1aa4fa0de6007cf011c

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