X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (av.hub.org [200.46.204.144]) by svr1.postgresql.org (Postfix) with ESMTP id 8ABFEDA810 for ; Mon, 21 Nov 2005 19:44:44 -0400 (AST) Received: from svr1.postgresql.org ([200.46.204.71]) by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024) with ESMTP id 94647-08 for ; Mon, 21 Nov 2005 23:44:45 +0000 (GMT) X-Greylist: from auto-whitelisted by SQLgrey- Received: from mail.Mi8.com (d01gw03.mi8.com [63.240.6.42]) by svr1.postgresql.org (Postfix) with ESMTP id 6B07BDA800 for ; Mon, 21 Nov 2005 19:44:39 -0400 (AST) Received: from 172.16.1.112 by mail.Mi8.com with ESMTP (- Welcome to Mi8 Corporation www.Mi8.com (D3)); Mon, 21 Nov 2005 18:44:37 -0500 X-Server-Uuid: E847189C-FC88-4913-9CD4-DE66914F83C0 Received: from MI8NYCMAIL06.Mi8.com ([172.16.1.175]) by D01SMTP02.Mi8.com with Microsoft SMTPSVC(6.0.3790.211); Mon, 21 Nov 2005 18:44:37 -0500 Received: from 208.54.15.129 ([208.54.15.129]) by MI8NYCMAIL06.Mi8.com ( [172.16.1.219]) via Exchange Front-End Server mi8owa.mi8.com ( [172.16.1.104]) with Microsoft Exchange Server HTTP-DAV ; Mon, 21 Nov 2005 18:44:36 -0500 User-Agent: Microsoft-Entourage/11.2.1.051004 Date: Mon, 21 Nov 2005 15:44:35 -0800 Subject: Re: Hardware/OS recommendations for large databases ( From: "Luke Lonergan" To: stange@rentec.com cc: "Greg Stark" , "Dave Cramer" , "Joshua Marsh" , pgsql-performance@postgresql.org Message-ID: Thread-Topic: [PERFORM] Hardware/OS recommendations for large databases ( Thread-Index: AcXu5hMWI9Vj4K+JQRCllSxfoX/kHQAD3P3t In-Reply-To: <438241E5.2010701@rentec.com> MIME-Version: 1.0 X-OriginalArrivalTime: 21 Nov 2005 23:44:37.0181 (UTC) FILETIME=[88583ED0:01C5EEF5] X-WSS-ID: 6F9C846F19O432430-01-01 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, score=2.283 required=5 tests=[AWL=-0.206, RCVD_IN_SORBS_WEB=1.236, RCVD_NUMERIC_HELO=1.253] X-Spam-Score: 2.283 X-Spam-Level: ** X-Archive-Number: 200511/429 X-Sequence-Number: 15686 Alan, Unless noted otherwise all results posted are for block device readahead set to 16M using "blockdev --setra=16384 ". All are using the 2.6.9-11 Centos 4.1 kernel. For those who don't have lmdd, here is a comparison of two results on an ext2 filesystem: ============================================================================ [root@modena1 dbfast1]# time bash -c "(dd if=/dev/zero of=/dbfast1/bigfile bs=8k count=800000 && sync)" 800000+0 records in 800000+0 records out real 0m33.057s user 0m0.116s sys 0m13.577s [root@modena1 dbfast1]# time lmdd if=/dev/zero of=/dbfast1/bigfile bs=8k count=800000 sync=1 6553.6000 MB in 31.2957 secs, 209.4092 MB/sec real 0m33.032s user 0m0.087s sys 0m13.129s ============================================================================ So lmdd with sync=1 is apparently equivalent to a sync after a dd. I use 2x memory with dd for the *READ* performance testing, but let's make sure things are synced on both sides for this set of comparisons. First, let's test ext2 versus "ext3, data=ordered", versus reiserfs versus xfs: