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Feature #15835

filestore: randomize split threshold

Added by Josh Durgin over 2 years ago. Updated 9 months ago.

Status:
Resolved
Priority:
Normal
Assignee:
Category:
Performance/Resource Usage
Target version:
-
Start date:
05/10/2016
Due date:
% Done:

0%

Source:
Support
Tags:
Backport:
jewel
Reviewed:
Affected Versions:
Component(RADOS):
Pull request ID:

Description

If the distribution of files is roughly even, many osds will reach the split threshold at the same time, causing them all to incur high latency as they all split directories at once.

A simple change that may mitigate this is to randomize the split threshold, similar to the randomized scrub threshold, so different osds split directories over a larger period of time.


Related issues

Copied to RADOS - Backport #22658: filestore: randomize split threshold Resolved

History

#1 Updated by Vikhyat Umrao over 2 years ago

  • Source changed from other to Support

#2 Updated by Peng Chen over 1 year ago

Hi! I am an undergrad student wishing to contribute to CEPH, and I would like to work on this issue. Please let me know.

Thanks,

Peng Chen

#3 Updated by Josh Durgin over 1 year ago

This one is more about performance testing, and at this point I think effort there is better spent on bluestore than filestore, and bluestore does not have internal splitting like this at all.

Perhaps you'd like to try http://tracker.ceph.com/issues/18629 ?

#4 Updated by Josh Durgin over 1 year ago

  • Backport set to jewel, kraken

#6 Updated by Nathan Cutler over 1 year ago

  • Status changed from New to Need Review

#7 Updated by Josh Durgin over 1 year ago

  • Status changed from Need Review to Resolved
  • Backport deleted (jewel, kraken)

Perf testing is not indicating much benefit, so I'd hold off on backporting this.

#8 Updated by Josh Durgin over 1 year ago

  • Backport set to jewel

I spoke too soon, there is significantly improved latency and throughput in longer running tests on several osds.

#9 Updated by Josh Durgin 10 months ago

  • Category deleted (OSD)
  • Status changed from Resolved to Pending Backport

#10 Updated by Josh Durgin 10 months ago

  • Project changed from Ceph to RADOS
  • Category set to Performance/Resource Usage
  • Assignee set to Josh Durgin

#11 Updated by Josh Durgin 10 months ago

#12 Updated by Nathan Cutler 9 months ago

  • Status changed from Pending Backport to Resolved

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