[Gluster-users] Fwd: Very slow performance when enabling tierd storage with SSD

Benjamin Kingston list at nexusnebula.net
Sun Sep 4 16:40:19 UTC 2016

Thanks for the help, see below:

On Sat, Sep 3, 2016 at 11:41 AM, Mohammed Rafi K C <rkavunga at redhat.com>

> Files created before attaching hot tier will be present on hot brick until
> it gets heated and migrated completely. During this time interval we won't
> get the benefit of hot storage since the files are served from cold brick.
The issue I'm having is that when the hot tier is added read from the
volume drops from 150MB/s (no tier) to 2-10MB/s (tier added). I experienced
this issue for a while even after the hot brick reached 90% capacity, so
many files were promoted.
I detached the hotbrick and verified there weren't any files left over, and
the performance was still effected.
It was only until I committed the detach that throughput returned to

Reattaching the hot tier immediately caused the issue to return until the
tier was again detach-committed

> For smallfiles (order of kbs), We are experiencing some performance issue
> mostly with  EC (disperse ) volume.
> Follow up questions,
> What is the volume type ? and version of glusterfs ?
The volume is a 2x replica on btrfs bricks that are luks encrypted. 2048K
GPT offset for 1st partition . Gluster 3.8.3, built aug 22 running on

> Does reread gives an equal performance when it hits the server ?
> reading any files with hot tier results in 2-10MB/s (node mounted volume
> via localhost6:/volume), reading them again any number of times does not
> improve performance

> Have you done any rename for those files ?
Some files have been renamed, however the 10GB test file has not it is the
original name/copy
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.gluster.org/pipermail/gluster-users/attachments/20160904/ee6a9314/attachment.html>

More information about the Gluster-users mailing list