Received: from maia.hub.org (maia-3.hub.org [200.46.204.243]) by mail.postgresql.org (Postfix) with ESMTP id 15AC76327BE for ; Mon, 26 Jul 2010 12:34:11 -0300 (ADT) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.243]) (amavisd-maia, port 10024) with ESMTP id 65065-01 for ; Mon, 26 Jul 2010 15:34:03 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from moutng.kundenserver.de (moutng.kundenserver.de [212.227.17.10]) by mail.postgresql.org (Postfix) with ESMTP id 7EA6D632723 for ; Mon, 26 Jul 2010 12:34:03 -0300 (ADT) Received: from [192.168.1.5] (static-71-179-240-8.bltmmd.fios.verizon.net [71.179.240.8]) by mrelayeu.kundenserver.de (node=mrbap1) with ESMTP (Nemesis) id 0Li1j8-1PQCdP3J22-00mdfF; Mon, 26 Jul 2010 17:34:02 +0200 Message-ID: <4C4DAAE8.3060501@2ndquadrant.com> Date: Mon, 26 Jul 2010 11:34:00 -0400 From: Greg Smith User-Agent: Thunderbird 2.0.0.24 (X11/20100317) MIME-Version: 1.0 To: Yeb Havinga CC: Matthew Wakeling , pgsql-performance@postgresql.org Subject: Re: Testing Sandforce SSD References: <4C4A9452.9070100@gmail.com> <4C4B1F84.5030306@2ndquadrant.com> <4C4C83DF.3010703@gmail.com> <4C4C8CCC.7080406@gmail.com> <4C4D6396.5020707@gmail.com> In-Reply-To: <4C4D6396.5020707@gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Provags-ID: V02:K0:UF1g4oB31Tx8r8R7brOzwqGRD1OTa25sdr/QtvULAR0 1+MFcy5Po/7Vw8xKJBBAkaPY2DvsCcfuo21Et8N8qD3TOv5nLe jfI4WRuyOfLzYfaARVb2uyFwJn1vcoK+kLWDkW33dwgPmZQvGj ZC1BfuMyO+icfCVlRXY0rIEHY7t6XQaecrvUcvN91kAOmreN1R 6+dtKjAvjZvjg98PkJGAtq3JPHhxrhmI5msxtyvFUY= X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-1.9 tagged_above=-10 required=5 tests=BAYES_00=-1.9, RCVD_IN_DNSWL_NONE=-0.0001 X-Spam-Level: X-Archive-Number: 201007/380 X-Sequence-Number: 39769 Yeb Havinga wrote: > Please remember that particular graphs are from a read/write pgbench > run on a bigger than RAM database that ran for some time (so with > checkpoints), on a *single* $435 50GB drive without BBU raid controller. To get similar *average* performance results you'd need to put about 4 drives and a BBU into a server. The worst-case latency on that solution is pretty bad though, when a lot of random writes are queued up; I suspect that's where the SSD will look much better. By the way: if you want to run a lot more tests in an organized fashion, that's what http://github.com/gregs1104/pgbench-tools was written to do. That will spit out graphs by client and by scale showing how sensitive the test results are to each. -- Greg Smith 2ndQuadrant US Baltimore, MD PostgreSQL Training, Services and Support greg@2ndQuadrant.com www.2ndQuadrant.us