Re: speed decrease since firefly,giant,hammer the 2nd try

[Stefan Priebe - Profihost AG <s.priebe@profihost.ag>]

Am 11.02.2015 um 08:44 schrieb Alexandre DERUMIER:
>>> same fio, same qemu, same vm, same host, same ceph dumpling storage, 
>>> different librados / librbd: 16k iop/s for random 4k writes
>>>
>>> What's wrong with librbd / librados2 since firefly?
> 
> Maybe could we bissect this ?
> 
> Maybe testing intermediate librbd releases between dumpling and firefly,
> 
> http://gitbuilder.ceph.com/ceph-deb-wheezy-x86_64-basic/ref/

Yes may be. Sadly i've currently another problem on my newest cluster
having strange kworker workload - i've never noticed before on any ceph
system. All writes are hanging - while using the same kernel as everywhere.

Stefan

> 
> could we give us an hint.
> 
> 
> ----- Mail original -----
> De: "Stefan Priebe" <s.priebe@profihost.ag>
> À: "ceph-devel" <ceph-devel@vger.kernel.org>
> Envoyé: Mardi 10 Février 2015 19:55:26
> Objet: speed decrease since firefly,giant,hammer the 2nd try
> 
> Hello, 
> 
> last year in june i already reported this but there was no real result. 
> (http://lists.ceph.com/pipermail/ceph-users-ceph.com/2014-July/041070.html) 
> 
> I then had the hope that this will be fixed itself when hammer is 
> released. Now i tried hammer an the results are bad as before. 
> 
> Since firefly librbd1 / librados2 are 20% slower for 4k random iop/s 
> than dumpling - this is also the reason why i still stick to dumpling. 
> 
> I've now modified my test again to be a bit more clear. 
> 
> Ceph cluster itself completely dumpling. 
> 
> librbd1 / librados from dumpling (fio inside qemu): 23k iop/s for random 
> 4k writes 
> 
> - stopped qemu 
> - cp -ra firefly_0.80.8/usr/lib/librados.so.2.0.0 /usr/lib/ 
> - cp -ra firefly_0.80.8/usr/lib/librbd.so.1.0.0 /usr/lib/ 
> - start qemu 
> 
> same fio, same qemu, same vm, same host, same ceph dumpling storage, 
> different librados / librbd: 16k iop/s for random 4k writes 
> 
> What's wrong with librbd / librados2 since firefly? 
> 
> Greets, 
> Stefan 
> 
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