Received: from localhost (maia-2.hub.org [200.46.204.187]) by postgresql.org (Postfix) with ESMTP id 973669FBE60 for ; Wed, 30 May 2007 11:07:51 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.187]) (amavisd-maia, port 10024) with ESMTP id 25138-05 for ; Wed, 30 May 2007 11:07:44 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.5 Received: from chip2og51.obsmtp.com (chip2og51.obsmtp.com [64.18.13.39]) by postgresql.org (Postfix) with SMTP id C022C9FBE34 for ; Wed, 30 May 2007 11:07:50 -0300 (ADT) Received: from source ([63.240.6.47]) (using TLSv1) by chip2ob51.postini.com ([64.18.5.12]) with SMTP; Wed, 30 May 2007 07:07:41 PDT Received: from 172.16.1.23 by mail.Mi8.com with ESMTP (- Welcome to Mi8 Corporation www.Mi8.com (D1)); Wed, 30 May 2007 10:07:33 -0400 X-Server-Uuid: 0764DD54-627B-4C45-B37D-789FBDEDA467 Received: from MI8NYCMAIL08.Mi8.com ([172.16.1.165]) by d01smtp09.Mi8.com with Microsoft SMTPSVC(6.0.3790.1830); Wed, 30 May 2007 10:07:33 -0400 Received: from 24.23.197.133 ([24.23.197.133]) by MI8NYCMAIL08.Mi8.com ( [172.16.1.190]) via Exchange Front-End Server mi8owa.mi8.com ( [172.16.1.104]) with Microsoft Exchange Server HTTP-DAV ; Wed, 30 May 2007 14:06:55 +0000 User-Agent: Microsoft-Entourage/11.3.3.061214 Date: Wed, 30 May 2007 07:06:54 -0700 Subject: Re: setting up raid10 with more than 4 drives From: "Luke Lonergan" To: "Peter Childs" cc: pgsql-performance@postgresql.org Message-ID: Thread-Topic: [PERFORM] setting up raid10 with more than 4 drives Thread-Index: Aceiw8a9BUii0Q63Edy5oAAX8s8Cag== In-Reply-To: MIME-Version: 1.0 X-OriginalArrivalTime: 30 May 2007 14:07:33.0859 (UTC) FILETIME=[DE7FD330:01C7A2C3] X-WSS-ID: 6A435AAF3002123573-01-01 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200705/609 X-Sequence-Number: 24999 Hi Peter, On 5/30/07 12:29 AM, "Peter Childs" wrote: > Good point, also if you had Raid 1 with 3 drives with some bit errors at least > you can take a vote on whats right. Where as if you only have 2 and they > disagree how do you know which is right other than pick one and hope... But > whatever it will be slower to keep in sync on a heavy write system. Much better to get a RAID system that checksums blocks so that "good" is known. Solaris ZFS does that, as do high end systems from EMC and HDS. - Luke