Received: from localhost (maia-4.hub.org [200.46.204.183]) by postgresql.org (Postfix) with ESMTP id EF2D69FB28C for ; Tue, 5 Dec 2006 10:50:06 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.183]) (amavisd-new, port 10024) with ESMTP id 78837-06 for ; Tue, 5 Dec 2006 10:50:00 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey-1.7.4 Received: from vms046pub.verizon.net (vms046pub.verizon.net [206.46.252.46]) by postgresql.org (Postfix) with ESMTP id B7A469FB28B for ; Tue, 5 Dec 2006 10:50:00 -0400 (AST) Received: from osgiliath.mathom.us ([71.246.251.8]) by vms046.mailsrvcs.net (Sun Java System Messaging Server 6.2-6.01 (built Apr 3 2006)) with ESMTPA id <0J9T00AU02J0Q4R3@vms046.mailsrvcs.net> for pgsql-performance@postgresql.org; Tue, 05 Dec 2006 08:49:49 -0600 (CST) Received: from localhost (localhost [127.0.0.1]) by osgiliath.mathom.us (Postfix) with ESMTP id 9F49B709C8 for ; Tue, 05 Dec 2006 09:49:46 -0500 (EST) Received: from osgiliath.mathom.us ([127.0.0.1]) by localhost (osgiliath.home.mathom.us [127.0.0.1]) (amavisd-new, port 10024) with LMTP id POX5Gfvb6PZq for ; Tue, 05 Dec 2006 09:49:43 -0500 (EST) Received: by osgiliath.mathom.us (Postfix, from userid 1000) id 8F5E0709CA; Tue, 05 Dec 2006 09:49:41 -0500 (EST) Date: Tue, 05 Dec 2006 09:49:41 -0500 From: Michael Stone Subject: Re: Bad iostat numbers In-reply-to: <33c6269f0612050457s4a8eb0eas662d7a50fb5dfa89@mail.gmail.com> To: pgsql-performance@postgresql.org Mail-followup-to: pgsql-performance@postgresql.org Message-id: <20061205144939.GA1622@mathom.us> MIME-version: 1.0 Content-type: text/plain; charset=us-ascii; format=flowed Content-disposition: inline X-Virus-Scanned: Debian amavisd-new at mathom.us X-Pgp-Fingerprint: 53 FF 38 00 E7 DD 0A 9C 84 52 84 C5 EE DF 7C 88 References: <33c6269f0612032317t9f0bc77n3ff791a5cd88fc80@mail.gmail.com> <33c6269f0612042221x5820e98bl96f8d0dc4a87bd3f@mail.gmail.com> <20061205121507.GZ1622@mathom.us> <33c6269f0612050457s4a8eb0eas662d7a50fb5dfa89@mail.gmail.com> User-Agent: Mutt/1.5.13 (2006-08-11) X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200612/76 X-Sequence-Number: 22132 On Tue, Dec 05, 2006 at 07:57:43AM -0500, Alex Turner wrote: >The problem I see with software raid is the issue of a battery backed unit: >If the computer loses power, then the 'cache' which is held in system >memory, goes away, and fubars your RAID. Since the Adaptec doesn't have a BBU, it's a lateral move. Also, this is less an issue of data integrity than performance; you can get exactly the same level of integrity, you just have to wait for the data to sync to disk. If you're read-mostly that's irrelevant. Mike Stone