Re: v0.80.8 and librbd performance

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On 04/14/2015 08:01 PM, shiva rkreddy wrote:
The clusters are in test environment, so its a new deployment of 0.80.9.
OS on the cluster nodes is reinstalled as well, so there shouldn't be
any fs aging unless the disks are slowing down.

The perf measurement is done initiating multiple cinder create/delete
commands and tracking the volume to be in available or completely gone
from "cinder list" output.

Even running  "rbd rm " command from cinder node results in similar
behaviour.

I'll try with  increasing  rbd_concurrent_management in ceph.conf.
  Is the param name rbd_concurrent_management or rbd-concurrent-management ?

'rbd concurrent management ops' - spaces, hyphens, and underscores are
equivalent in ceph configuration.

A log with 'debug ms = 1' and 'debug rbd = 20' from 'rbd rm' on both versions might give clues about what's going slower.

Josh

On Tue, Apr 14, 2015 at 12:36 PM, Josh Durgin <jdurgin@xxxxxxxxxx
<mailto:jdurgin@xxxxxxxxxx>> wrote:

    I don't see any commits that would be likely to affect that between
    0.80.7 and 0.80.9.

    Is this after upgrading an existing cluster?
    Could this be due to fs aging beneath your osds?

    How are you measuring create/delete performance?

    You can try increasing rbd concurrent management ops in ceph.conf on
    the cinder node. This affects delete speed, since rbd tries to
    delete each object in a volume.

    Josh


    *From:* shiva rkreddy <shiva.rkreddy@xxxxxxxxx
    <mailto:shiva.rkreddy@xxxxxxxxx>>
    *Sent:* Apr 14, 2015 5:53 AM
    *To:* Josh Durgin
    *Cc:* Ken Dreyer; Sage Weil; Ceph Development; ceph-users@xxxxxxxx
    <mailto:ceph-users@xxxxxxxx>
    *Subject:* Re: v0.80.8 and librbd performance

        Hi Josh,

        We are using firefly 0.80.9 and see both cinder create/delete
        numbers slow down compared 0.80.7.
        I don't see any specific tuning requirements and our cluster is
        run pretty much on default configuration.
        Do you recommend any tuning or can you please suggest some log
        signatures we need to be looking at?

        Thanks
        shiva

        On Wed, Mar 4, 2015 at 1:53 PM, Josh Durgin <jdurgin@xxxxxxxxxx
        <mailto:jdurgin@xxxxxxxxxx>> wrote:

            On 03/03/2015 03:28 PM, Ken Dreyer wrote:

                On 03/03/2015 04:19 PM, Sage Weil wrote:

                    Hi,

                    This is just a heads up that we've identified a
                    performance regression in
                    v0.80.8 from previous firefly releases.  A v0.80.9
                    is working it's way
                    through QA and should be out in a few days.  If you
                    haven't upgraded yet
                    you may want to wait.

                    Thanks!
                    sage


                Hi Sage,

                I've seen a couple Redmine tickets on this (eg
                http://tracker.ceph.com/__issues/9854
                <http://tracker.ceph.com/issues/9854> ,
                http://tracker.ceph.com/__issues/10956
                <http://tracker.ceph.com/issues/10956>). It's not
                totally clear to me
                which of the 70+ unreleased commits on the firefly
                branch fix this
                librbd issue.  Is it only the three commits in
                https://github.com/ceph/ceph/__pull/3410
                <https://github.com/ceph/ceph/pull/3410> , or are there
                more?


            Those are the only ones needed to fix the librbd performance
            regression, yes.

            Josh

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