X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (av.hub.org [200.46.204.144]) by postgresql.org (Postfix) with ESMTP id 18DE49DC80C for ; Tue, 27 Dec 2005 15:18:34 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024) with ESMTP id 71906-06 for ; Tue, 27 Dec 2005 15:18:28 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey- Received: from mail.mi8.com (d01gw02.mi8.com [63.240.6.46]) by postgresql.org (Postfix) with ESMTP id 0DFBA9DC9C9 for ; Tue, 27 Dec 2005 15:18:25 -0400 (AST) Received: from 172.16.1.110 by mail.mi8.com with ESMTP (- Welcome to Mi8 Corporation www.Mi8.com (D2)); Tue, 27 Dec 2005 14:18:21 -0500 X-Server-Uuid: 7829E76E-BB9E-4995-8473-3C0929DF7DD1 Received: from MI8NYCMAIL06.Mi8.com ([172.16.1.175]) by D01SMTP01.Mi8.com with Microsoft SMTPSVC(6.0.3790.1830); Tue, 27 Dec 2005 14:18:21 -0500 Received: from 67.103.45.218 ([67.103.45.218]) by MI8NYCMAIL06.Mi8.com ( [172.16.1.219]) via Exchange Front-End Server mi8owa.mi8.com ( [172.16.1.106]) with Microsoft Exchange Server HTTP-DAV ; Tue, 27 Dec 2005 19:18:20 +0000 User-Agent: Microsoft-Entourage/11.2.1.051004 Date: Tue, 27 Dec 2005 11:18:19 -0800 Subject: Re: What's the best hardver for PostgreSQL 8.1? From: "Luke Lonergan" To: "Bruce Momjian" , "Ron" cc: "Michael Stone" , pgsql-performance@postgresql.org Message-ID: Thread-Topic: [PERFORM] What's the best hardver for PostgreSQL 8.1? Thread-Index: AcYLDlYxGi/XaYB3RzyLteeUIiYGQAAC/VJ5 In-Reply-To: <200512271751.jBRHpw307927@candle.pha.pa.us> MIME-Version: 1.0 X-OriginalArrivalTime: 27 Dec 2005 19:18:21.0396 (UTC) FILETIME=[4CE7E940:01C60B1A] X-WSS-ID: 6FAF4CF73TO1794667-01-01 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=1.272 required=5 tests=[AWL=0.019, RCVD_NUMERIC_HELO=1.253] X-Spam-Score: 1.272 X-Spam-Level: * X-Archive-Number: 200512/638 X-Sequence-Number: 16459 Bruce, On 12/27/05 9:51 AM, "Bruce Momjian" wrote: > Historically, I have heard that RAID5 is only faster than RAID10 if > there are six or more drives. I think the real question here is "faster for what?" Also, just like the optimizer tunables for cpu/disk/memory speed relationships, the standing guidance for RAID has become outdated. Couple that with the predominance of really bad hardware RAID controllers and people not testing them or reporting their performance (HP, Adaptec, LSI, Dell) and we've got a mess. All we can really do is report success with various point solutions. RAID5 and RAID50 work fine for our customers who do OLAP type applications which are read-mostly. However, it only works well on good hardware and software, which at this time include the HW RAID controllers from 3Ware and reputedly Areca and SW using Linux SW RAID. I've heard that the external storage RAID controllers from EMC work well, and I'd suspect there are others, but none of the host-based SCSI HW RAID controllers I've tested work well on Linux. I say Linux, because I'm pretty sure that the HP smartarray controllers work well on Windows, but the Linux driver is so bad I'd say it doesn't work at all. WRT RAID10, it seems like throwing double the number of disks at the problems is something to be avoided if possible, though the random write performance may be important for OLTP. I think this assertion should be retested however in light of the increased speed of checksumming hardware and / or CPUs and faster, more effective drive electronics (write combining, write cache, etc). - Luke