Received: from makus.postgresql.org (makus.postgresql.org [98.129.198.125]) by mail.postgresql.org (Postfix) with ESMTP id EB28B514018 for ; Fri, 9 Mar 2012 07:16:18 -0400 (AST) Received: from campbell-lange.net ([93.191.37.68]) by makus.postgresql.org with esmtp (Exim 4.72) (envelope-from ) id 1S5xo1-0005yi-IA for pgsql-performance@postgresql.org; Fri, 09 Mar 2012 11:16:18 +0000 Received: from 78-105-14-9.zone3.bethere.co.uk ([78.105.14.9] helo=rory-x220.config) by campbell-lange.net with esmtpsa (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.72) (envelope-from ) id 1S5xnn-0008Ha-8L for pgsql-performance@postgresql.org; Fri, 09 Mar 2012 11:16:03 +0000 Received: from rory by rory-x220.config with local (Exim 4.77) (envelope-from ) id 1S5xni-0005wK-Gd for pgsql-performance@postgresql.org; Fri, 09 Mar 2012 11:15:58 +0000 Date: Fri, 9 Mar 2012 11:15:58 +0000 From: Rory Campbell-Lange To: pgsql-performance@postgresql.org Subject: Comments requested on IO performance : new db server Message-ID: <20120309111558.GA22643@campbell-lange.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) X-Pg-Spam-Score: -1.9 (-) X-Archive-Number: 201203/83 X-Sequence-Number: 46533 I've taken the liberty of reposting this message as my addendum to a long thread that I started on the subject of adding a new db server to our existing 4-year old workhorse got lost in discussion. Our workload is several small databases totalling less than 40GB of disk space. The proposed system has 48GB RAM, 2 * quad core E5620 @ 2.40GHz and 4 WD Raptors behind an LSI SAS card. Our supplier has just run a set of tests on the machine we intend to buy. The test rig had the following setup: LSI MegaRAID SAS 9260-8i Firmware: 12.12.0-0090 Kernel: 2.6.39.4 Hard disks: 4x WD6000BLHX Test done on 256GB volume BS = blocksize in bytes The test tool is fio. I'd be grateful to know if the results below are considered acceptable. An ancillary question is whether a 4096 block size is a good idea. I suppose we will be using XFS which I understand has a default block size of 4096 bytes. RAID 10 -------------------------------------- Read sequential BS MB/s IOPs 512 0129.26 264730.80 1024 0229.75 235273.40 4096 0363.14 092965.50 16384 0475.02 030401.50 65536 0472.79 007564.65 131072 0428.15 003425.20 -------------------------------------- Write sequential BS MB/s IOPs 512 0036.08 073908.00 1024 0065.61 067192.60 4096 0170.15 043560.40 16384 0219.80 014067.57 65536 0240.05 003840.91 131072 0243.96 001951.74 -------------------------------------- Random read BS MB/s IOPs 512 0001.50 003077.20 1024 0002.91 002981.40 4096 0011.59 002968.30 16384 0044.50 002848.28 65536 0156.96 002511.41 131072 0170.65 001365.25 -------------------------------------- Random write BS MB/s IOPs 512 0000.53 001103.60 1024 0001.15 001179.20 4096 0004.43 001135.30 16384 0017.61 001127.56 65536 0061.39 000982.39 131072 0079.27 000634.16 -------------------------------------- -- Rory Campbell-Lange rory@campbell-lange.net Campbell-Lange Workshop www.campbell-lange.net 0207 6311 555 3 Tottenham Street London W1T 2AF Registered in England No. 04551928