[LU-16857] Allocate OST objects from spill pool when pool quota exceeded

• Type: Improvement
• Resolution: Unresolved
• Priority: Minor
• Affects Version/s: Lustre 2.14.0, Lustre 2.16.0, Lustre 2.15.0
• Severity: 3
• Assignee: WC Triage
• Reporter: Andreas Dilger

Description

In cases where PFL layouts include a flash component at the start of the file to handle small files, and if the user runs out of pool quota on the flash OSTs then the filesystem becomes almost unusable for them, even if they have quota remaining on the disk pool. It would be possible for them to change the default layout for all of their direvtories, but it would need to be changed back once they are below quota again, which is inconvenient.

When allocating OST objects for a component that has specified an OST pool, but the user has exceeded their OST pool quota, the objects should be allocated from the spill pool, if it is configured. Otherwise, the MDS will allocate OST objects that the user cannot write without getting EDQUOT.

Issue Links

• is related to: LU-11023 OST Pool Quotas
• is related to: LU-13058 Intermediate component removal (PFL/SEL)