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Bug #20594

mds: cache limits should be expressed in memory usage, not inode count

Added by Patrick Donnelly over 2 years ago. Updated about 2 years ago.

Status:
Resolved
Priority:
Urgent
Category:
Performance/Resource Usage
Target version:
% Done:

0%

Source:
Development
Tags:
Backport:
luminous
Regression:
No
Severity:
3 - minor
Reviewed:
Affected Versions:
ceph-qa-suite:
Component(FS):
MDS
Labels (FS):
Pull request ID:
Crash signature:

Description

Cached inode count (mds_cache_size) is an imperfect limit for what we really want. We frequently have to tell users/customers to tune this based on the amount of memory they want to consume for the MDS which is unacceptable.

Instead, use mempools with the cached objects to track memory usage and limit based on that.

BZ: https://bugzilla.redhat.com/show_bug.cgi?id=1464976


Related issues

Related to fs - Feature #4504: mds: trim based on total memory usage Resolved 03/19/2013
Related to fs - Feature #4502: mds: Make the MemoryModel useful New 03/19/2013
Related to fs - Bug #21402: mds: move remaining containers in CDentry/CDir/CInode to mempool Resolved 09/15/2017
Related to fs - Feature #36663: mds: adjust cache memory limit automatically via target that tracks RSS In Progress
Copied to fs - Backport #21384: luminous: mds: cache limits should be expressed in memory usage, not inode count Resolved

History

#1 Updated by Ian Colle over 2 years ago

  • Assignee set to Patrick Donnelly

#2 Updated by Greg Farnum over 2 years ago

See #4504 and associated MemoryModel tickets.

#3 Updated by Patrick Donnelly over 2 years ago

  • Related to Feature #4504: mds: trim based on total memory usage added

#4 Updated by Patrick Donnelly over 2 years ago

  • Related to Feature #4502: mds: Make the MemoryModel useful added

#5 Updated by Patrick Donnelly over 2 years ago

  • Status changed from New to In Progress

#6 Updated by Sage Weil over 2 years ago

  • Priority changed from Immediate to Urgent

#7 Updated by Patrick Donnelly about 2 years ago

  • Status changed from In Progress to Fix Under Review
  • Target version set to v12.2.1
  • Backport set to luminous

#8 Updated by Patrick Donnelly about 2 years ago

  • Status changed from Fix Under Review to Pending Backport

#9 Updated by Patrick Donnelly about 2 years ago

  • Copied to Backport #21384: luminous: mds: cache limits should be expressed in memory usage, not inode count added

#10 Updated by Patrick Donnelly about 2 years ago

  • Related to Bug #21402: mds: move remaining containers in CDentry/CDir/CInode to mempool added

#11 Updated by Patrick Donnelly about 2 years ago

  • Status changed from Pending Backport to Resolved

#12 Updated by Patrick Donnelly about 1 year ago

  • Related to Feature #36663: mds: adjust cache memory limit automatically via target that tracks RSS added

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