[LU-16203] zero records and empty plain llogs in update llog catalog

• Type: Bug
• Resolution: Fixed
• Priority: Major
• Fix Version/s: Lustre 2.16.0
• Labels: llog
• Severity: 3
• Assignee: Mikhail Pershin
• Reporter: Mikhail Pershin

Description

there are reported situations when llog catalog has zeros at record place in the middle of llog. Also reported catalog has created but never used plain llogs or partially used though never deleted plain llogs in the middle. 

Whole problem could be related to 'next' llog handling for remote llog, it looks like several next llogs could be created at the same time with only one (the last one) used actually. If some of creation failed for any reason, the last one still would have all bits are set in header update and will write it down while records are missing. That would explain zeroed holes in the middle of catalog. Details are not clear yet, it is to investigate.

Meanwhile catalog llog could still be processed even with such corruptions and that could help to handle such situations gracefully while problem is being investigated

Issue Links

• is related to: LU-15938 MDT recovery did not finish due to corrupt llog record