From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-out2.uio.no ([129.240.10.58]:56844 "EHLO mail-out2.uio.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752135Ab2EQQRC (ORCPT ); Thu, 17 May 2012 12:17:02 -0400 Received: from mail-mx3.uio.no ([129.240.10.44]) by mail-out2.uio.no with esmtp (Exim 4.75) (envelope-from ) id 1SV3Ns-0003QJ-GN for fio@vger.kernel.org; Thu, 17 May 2012 18:17:00 +0200 Received: from 7.123.45.31.customer.cdi.no ([31.45.123.7] helo=heritage.uio.no) by mail-mx3.uio.no with esmtpsa (TLSv1:AES256-SHA:256) user jb (Exim 4.76) (envelope-from ) id 1SV3Ns-0008LY-0H for fio@vger.kernel.org; Thu, 17 May 2012 18:17:00 +0200 Message-ID: <4FB52477.4050407@usit.uio.no> Date: Thu, 17 May 2012 18:16:55 +0200 From: =?ISO-8859-1?Q?Jarle_Bj=F8rgeengen?= Reply-To: fio@vger.kernel.org MIME-Version: 1.0 Subject: Re: blktrace with fio replay for benchmarking vendor offerings References: <4FB3FE27.3030302@usit.uio.no> <4FB417E0.5080802@cesnet.cz> In-Reply-To: <4FB417E0.5080802@cesnet.cz> Content-Type: text/plain; charset="iso-8859-1"; format="flowed" Content-Transfer-Encoding: quoted-printable Sender: fio-owner@vger.kernel.org List-Id: fio@vger.kernel.org To: Cc: fio@vger.kernel.org On 05/16/2012 11:10 PM, Jiri Horky wrote: > Hi Jarle, > > On 05/16/2012 09:21 PM, Jarle Bj=EF=BF=BDrgeengen wrote: >> Hello, >> >> I'm involved in the purchasing process of block storage systems, and >> research viable benchmarking strategies for specifying and verifying >> performance requirements. >> >> Ideally I would like to capture our traces of our current daily >> production workload with blktrace, attach the traces to the tender and >> require the configuration to be able to run 2x that kind of workload. >> During acceptance I would like to hook enough hardware to saturate the >> system with the same workload, and measure that the requirement has >> been met. >> >> I'm interested in comments about the practical viability of such >> approach if anyone have similar experiences. >> > actually, I am in the very same situation at Institute of Physics, where > we annually buy some 1PB of raw disk space (the money equivalent). We > ended up with very similar approach that you described. We use IOreplay > from IOapps (http://code.google.com/p/ioapps/) application to run the > load previously recorded by strace. So it is done on a file level > instead of the block level. This clearly has its advantages (you may use > different file system, benchmarks are not fatal for running systems > etc.), but of course some drawbacks as well (strace overhead, etc., see > webpage). If you are interested and have any more question/suggestion > about the IOreplay, just email me, I actually wrote it as a part of my > master thesis. Thanks for the tip I'll check out IOapps. >> Some open questions: >> >> How safe is it to run blktrace on critical production environment? >> What precautions should be made? >> >> Given that the current system consists of 3 HP EVA800 with X number of >> LUNS about 50 hosts, and the new system likely is a single system with >> 5 new servers running at at full speed, how much value will the >> benchmark provide compared to "real world" ? Should I create equally >> many luns and distribute load across the 5 machines? >> >> Is it best to scale the workload to 2X replaying all traces >> simultanously with one fio-trace-replay/lun, and then dublicate alle >> replays so that each lun serves two fio-replays rather than one, and >> then 3 and so on. >> >> Any thoughts or comments are very much appreciated. > I would say that all above heavily depends on your environment, whether > the access pattern is similar to all LUNS and whether all LUNS are more > or less expected to expand similarly in the future. Personally, I would > go with settings that are simpler to setup (from the options you have > proposed) unless you really know your future requirements and you are > sure that the results obtained in both ways differ significantly. Thanks. - Jarle Bj=EF=BF=BDrgeengen