[LU-5726] MDS buffer not freed when deleting files

• Type: Bug
• Resolution: Fixed
• Priority: Blocker
• Fix Version/s: Lustre 2.7.0, Lustre 2.5.4
• Affects Version/s: Lustre 2.4.3
• Environment: CentOS 6.5; Kernel 2.6.32-358.23.2
• Severity: 3
• Assignee: Niu Yawei (Inactive)
• Reporter: Rick Mohr

Description

When deleting large numbers of files, memory usage on the MDS server grows significantly. Attempts to reclaim memory by dropping caches only results in some of the memory being freed. The buffer usage continues to grow until eventually the MDS server starts OOMing.

The rate at which the buffer usage grows seems to vary but looks like it might be based on the number of clients that are deleting files and the speed at which the files are deleted.

Issue Links

• is related to: LU-5333 rm cause MDS to complain hung tasks and disconnecting clients
• is related to: LU-5841 Lustre 2.4.2 MDS, hitting OOM errors