Received: from localhost (unknown [200.46.204.183]) by mail.postgresql.org (Postfix) with ESMTP id F377764FC52 for ; Mon, 24 Nov 2008 09:24:05 -0400 (AST) Received: from mail.postgresql.org ([200.46.204.86]) by localhost (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 10216-01 for ; Mon, 24 Nov 2008 09:24:03 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from elasmtp-curtail.atl.sa.earthlink.net (elasmtp-curtail.atl.sa.earthlink.net [209.86.89.64]) by mail.postgresql.org (Postfix) with ESMTP id 5D2AB64FC44 for ; Mon, 24 Nov 2008 09:24:03 -0400 (AST) Received: from [205.201.149.100] (helo=[10.0.129.1]) by elasmtp-curtail.atl.sa.earthlink.net with esmtpsa (TLSv1:AES256-SHA:256) (Exim 4.67) (envelope-from ) id 1L4bQ1-0007C2-7s; Mon, 24 Nov 2008 08:24:01 -0500 Message-ID: <492AAAEA.9030106@netwolves.com> Date: Mon, 24 Nov 2008 08:23:54 -0500 From: Steve Clark User-Agent: Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:1.7.13) Gecko/20080707 X-Accept-Language: en-us, en MIME-Version: 1.0 To: glynastill@yahoo.co.uk CC: Scott Marlowe , pgsql-performance@postgresql.org Subject: Re: Perc 3 DC References: <707711.35257.qm@web23603.mail.ird.yahoo.com> In-Reply-To: <707711.35257.qm@web23603.mail.ird.yahoo.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-ELNK-Trace: a437fbc6971e80f61aa676d7e74259b7b3291a7d08dfec79b8eb344a1919b399a2ce82412b194471350badd9bab72f9c350badd9bab72f9c350badd9bab72f9c X-Originating-IP: 205.201.149.100 X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=0 tagged_above=0 required=5 tests=none X-Spam-Level: X-Archive-Number: 200811/227 X-Sequence-Number: 31958 Glyn Astill wrote: > --- On Sat, 22/11/08, Scott Marlowe wrote: > > >>You really have two choices. First is to try and use it as >>a plain >>SCSI card, maybe with caching turned on, and do the raid in >>software. >>Second is to cut it into pieces and make jewelry out of it. > > > Haha, I'm not really into jewelry, although I had thought of smacking it into a pile of dust with a lump hammer, that's much more my thing. > > >> Anything >>before the Perc 6 series is seriously brain damaged, and >>the Perc6 >>brings the dell raid array line squarly in line with a 5 >>year old LSI >>megaraid, give or take. And that's being generous. >> > > > Well this card thinks it's a 5 year old lsi megaraid. I've got a pile of perc5i megaraid paperweights on my desk at work, so this was kinda expected really. > > >>>I've tried writeback and write through modes, >> >>tried changing cache flush times, disabled and enabled >>multiple PCI delayed transactions, all seem to have little >>effect. >> >>Yeah, it's like trying to performance tune a yugo. >> > > > Did I mention I drive a yugo? > > >>>Finally I decided to wave goodbye to Dell's >> >>firmware. LSI has it down as a MegaRAID 493 elite 1600, so I >>flashed it with their latest firmware. Doesn't seem to >>have helped either though. >> >>Does it have a battery backup module? Often you can't >>really turn on >>write-back without one. That would certainly slow things >>down. But >>you should certainly expect > 20 M/s on a modern RAID >>controller >>writing out to a 4 disk RAID10 >> > > > Yeah the battery's on it, that and the 128Mb is really the only reason I thought I'd give it a whirl. > > > > Is the battery functioning? We found that the unit had to be on and charged before write back caching would work.