Re: v0.80.8 and librbd performance

shiva rkreddy <shiva.rkreddy@xxxxxxxxx> · Tue, 14 Apr 2015 23:27:24 -0500

Retried the test with by setting: rbd_concurrent_management_ops and rbd-concurrent-management-ops to 20 (default 10?) and didn't see any difference in the delete time.

Steps:
1. Create 20, 500GB volumes
2. run : rbd -n clientkey -p cindervols rbd rm $volumeId &
3. run rbd ls command in with 1 second sleep and capture output  : rbd -n clientkey -p cindervols rbd ls 

It took the same amount of time to remove all entries in the pool when the ops setting was default.

Thanks

On Tue, Apr 14, 2015 at 10:01 PM, shiva rkreddy <shiva.rkreddy@xxxxxxxxx> 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 ?

On Tue, Apr 14, 2015 at 12:36 PM, Josh Durgin <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>
Sent: Apr 14, 2015 5:53 AM
To: Josh Durgin
Cc: Ken Dreyer; Sage Weil; Ceph Development; 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> 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/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 , or are there more?

Those are the only ones needed to fix the librbd performance

regression, yes.

Josh

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