From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Kirkwood Subject: Re: Ceph RBD performance - random writes Date: Thu, 09 Aug 2012 11:36:15 +1200 Message-ID: <5022F7EF.2020007@catalyst.net.nz> References: <5021F6D1.7000004@catalyst.net.nz> <5022B3F4.5050109@inktank.com> <5022E121.4070004@inktank.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from bertrand.catalyst.net.nz ([202.78.240.40]:42941 "EHLO mail.catalyst.net.nz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753039Ab2HHXgT (ORCPT ); Wed, 8 Aug 2012 19:36:19 -0400 In-Reply-To: <5022E121.4070004@inktank.com> Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Mark Nelson Cc: Josh Durgin , ceph-devel@vger.kernel.org On 09/08/12 09:58, Mark Nelson wrote: > > For what it's worth, with mostly default settings I was seeing about > 8MB/s to dell branded samsung SSDs with 4k IOs using rados bench. > That was with 256 concurrent client requests. This is definitely > something we are working hard on tracking down. > Right (FWIW I think the Dells are actually Toshiba devices - and are pretty good). This is what I get doing the rados bench for 1M and 4K blocks: $ rados bench -b 1048576 -t 256 -p rbd 100 write Total writes made: 3879 Write size: 1048576 Bandwidth (MB/sec): 38.414 Stddev Bandwidth: 40.157 Max bandwidth (MB/sec): 174 Min bandwidth (MB/sec): 0 Average Latency: 6.57279 Stddev Latency: 6.20373 Max latency: 28.531 Min latency: 0.435691 $ rados bench -b 4096 -t 256 -p rbd 100 write Total writes made: 4851 Write size: 4096 Bandwidth (MB/sec): 0.179 Stddev Bandwidth: 0.378904 Max bandwidth (MB/sec): 3.22266 Min bandwidth (MB/sec): 0 Average Latency: 5.60013 Stddev Latency: 8.18634 Max latency: 22.6542 Min latency: 0.020016