Bug 1554743
Summary: | [EC] Read performance of EC volume exported over gNFS is significantly lower than write performance | |||
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Product: | [Community] GlusterFS | Reporter: | Ashish Pandey <aspandey> | |
Component: | disperse | Assignee: | Ashish Pandey <aspandey> | |
Status: | CLOSED CURRENTRELEASE | QA Contact: | ||
Severity: | unspecified | Docs Contact: | ||
Priority: | unspecified | |||
Version: | mainline | CC: | bugs | |
Target Milestone: | --- | |||
Target Release: | --- | |||
Hardware: | Unspecified | |||
OS: | Unspecified | |||
Whiteboard: | ||||
Fixed In Version: | glusterfs-v4.1.0 | Doc Type: | If docs needed, set a value | |
Doc Text: | Story Points: | --- | ||
Clone Of: | ||||
: | 1557904 1557906 1558352 (view as bug list) | Environment: | ||
Last Closed: | 2018-06-20 18:01:56 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: | 1557904, 1557906, 1558352, 1559084 |
Description
Ashish Pandey
2018-03-13 09:36:26 UTC
REVIEW: https://review.gluster.org/19703 (cluster/ec: Change default read policy to gfid-hash) posted (#2) for review on master by Ashish Pandey COMMIT: https://review.gluster.org/19703 committed in master by "Ashish Pandey" <aspandey> with a commit message- cluster/ec: Change default read policy to gfid-hash Problem: Whenever we read data from file over NFS, NFS reads more data then requested and caches it. Based on the stat information it makes sure that the cached/pre-read data is valid or not. Consider 4 + 2 EC volume and all the bricks are on differnt nodes. In EC, with round-robin read policy, reads are sent on different set of data bricks. This way, it balances the read fops to go on all the bricks and avoid heating UP (overloading) same set of bricks. Due to small difference in clock speed, it is possible that we get minor difference for atime, mtime or ctime for different bricks. That might cause a different stat returned to NFS based on which NFS will discard cached/pre-read data which is actually not changed and could be used. Solution: Change read policy for EC as gfid-hash. That will force all the read to go to same set of bricks. Change-Id: I825441cc519e94bf3dc3aa0bd4cb7c6ae6392c84 BUG: 1554743 Signed-off-by: Ashish Pandey <aspandey> This bug is getting closed because a release has been made available that should address the reported issue. In case the problem is still not fixed with glusterfs-v4.1.0, please open a new bug report. glusterfs-v4.1.0 has been announced on the Gluster mailinglists [1], packages for several distributions should become available in the near future. Keep an eye on the Gluster Users mailinglist [2] and the update infrastructure for your distribution. [1] http://lists.gluster.org/pipermail/announce/2018-June/000102.html [2] https://www.gluster.org/pipermail/gluster-users/ |