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

[Alexandre DERUMIER <aderumier@odiso.com>]

>>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/

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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