Bug 1337018

Summary: [RFE] filestore: randomize split threshold
Product: [Red Hat Storage] Red Hat Ceph Storage Reporter: Vikhyat Umrao <vumrao>
Component: RADOSAssignee: Josh Durgin <jdurgin>
Status: CLOSED ERRATA QA Contact: shylesh <shmohan>
Severity: urgent Docs Contact:
Priority: urgent    
Version: 1.3.2CC: anharris, ceph-eng-bugs, dzafman, hnallurv, icolle, jdurgin, kchai, tbrekke, uboppana
Target Milestone: rcKeywords: FutureFeature
Target Release: 3.0   
Hardware: x86_64   
OS: Linux   
Whiteboard:
Fixed In Version: RHEL: ceph-12.1.2-1.el7cp Ubuntu: ceph_12.1.2-2redhat1xenial Doc Type: Bug Fix
Doc Text:
.Split threshold is now randomized Previously, the split threshold was not randomized, so that many OSDs reached it at the same time. As a consequence, such OSDs incurred high latency because they all split directories at once. With this update, the split threshold is randomized which ensures that OSDs split directories over a large period of time.
Story Points: ---
Clone Of:
: 1533266 (view as bug list) Environment:
Last Closed: 2017-12-05 23:29:38 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 1258382, 1494421    

Description Vikhyat Umrao 2016-05-18 04:48:41 UTC
Description of problem:
[RFE] filestore: randomize split threshold

- 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.

For more information Please Check Bugzilla : https://bugzilla.redhat.com/show_bug.cgi?id=1291632 and specific comment#55 : https://bugzilla.redhat.com/show_bug.cgi?id=1332874#c55



Version-Release number of selected component (if applicable):
Red Hat Ceph Storage 1.3.2
Upstream Hammer

Comment 9 Josh Durgin 2017-05-18 21:01:37 UTC
*** Bug 1219974 has been marked as a duplicate of this bug. ***

Comment 10 Ian Colle 2017-08-01 03:49:38 UTC
https://github.com/ceph/ceph/pull/15689 Merged

Comment 17 errata-xmlrpc 2017-12-05 23:29:38 UTC
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2017:3387