[LU-17234] LFSCK layout repair to handle orphan objects on removed MDTs

Related — Fri, 27 Oct 2023 19:44:12 +0000

Running LFSCK on a system where an MDT has been removed is currently not able to repair orphan OST objects. Normally, during OST orphan repair the objects are linked to an MDT inode in the .lustre/lost+found/MDTxxxx directory based on the parent FID stored in the filter_fid. This combines all OST objects to a single parent FID and will consolidate them into a single file and regenerate the layout as much as possible.

However, if the MDT has been removed, then the .lustre/lost+found/MDTxxxx directory will reference an object on that MDT and it is no longer accessible.

There needs to be some way to remove the MDTxxxx directory and create a new directory on a different MDT to hold those inodes. As part of this, the orphan handling needs to know which MDT to use to create the inodes, since I think it currently depends on running the orphan handling on each MDT separately.

Whamcloud Community JIRA

[LU-17234] LFSCK layout repair to handle orphan objects on removed MDTs