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Bug #53952
closedmds: mds_oft_prefetch_dirfrags default to false
% Done:
0%
Source:
Tags:
Backport:
octopus,pacific,quincy
Regression:
No
Severity:
3 - minor
Reviewed:
Affected Versions:
ceph-qa-suite:
Component(FS):
MDS
Labels (FS):
Pull request ID:
Crash signature (v1):
Crash signature (v2):
Description
The oft dirfrag prefetch is unpredictable and dangerous because it can
delay rejoin by several minutes and balloon memory usage well beyond the
mds_cache_memory_limit. In the worst cases this can cause an OOM loop if
the memory required for prefetch exceeds the physical memory.
The PR which introduced mds_oft_prefetch_dirfrags also optimized the
client behaviour to eliminate the bad effects of disabling dirfrags
prefetch. And commit d3946e3 has been
testing setting this option to false.
We therefore should default the option to false. Operators can still
manually enable it if they know it can speedup their use-cases.
Related-to: https://tracker.ceph.com/issues/45835
Updated by Dan van der Ster about 2 years ago
- Status changed from New to Fix Under Review
Updated by Venky Shankar about 2 years ago
- Backport changed from octopus,pacific to octopus,pacific,quincy
Updated by Venky Shankar about 2 years ago
- Status changed from Fix Under Review to Pending Backport
Updated by Backport Bot about 2 years ago
- Copied to Backport #54194: pacific: mds: mds_oft_prefetch_dirfrags default to false added
Updated by Backport Bot about 2 years ago
- Copied to Backport #54195: octopus: mds: mds_oft_prefetch_dirfrags default to false added
Updated by Backport Bot about 2 years ago
- Copied to Backport #54196: quincy: mds: mds_oft_prefetch_dirfrags default to false added
Updated by Konstantin Shalygin over 1 year ago
- Tracker changed from Fix to Bug
- Status changed from Pending Backport to Resolved
- Tags deleted (
backport_processed) - Regression set to No
- Severity set to 3 - minor
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