Received: from localhost (unknown [200.46.204.183]) by postgresql.org (Postfix) with ESMTP id CBF54650F00 for ; Wed, 25 Jun 2008 12:53:36 -0300 (ADT) Received: from postgresql.org ([200.46.204.86]) by localhost (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 13946-01-4 for ; Wed, 25 Jun 2008 12:53:30 -0300 (ADT) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from yx-out-2324.google.com (yx-out-2324.google.com [74.125.44.29]) by postgresql.org (Postfix) with ESMTP id 92491650F2B for ; Wed, 25 Jun 2008 12:53:20 -0300 (ADT) Received: by yx-out-2324.google.com with SMTP id 8so580896yxb.73 for ; Wed, 25 Jun 2008 08:53:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to :subject:cc:in-reply-to:mime-version:content-type :content-transfer-encoding:content-disposition:references; bh=/Ierx5gZU+DoJdhE9eTsCKyJtQTww4WtKvOpB73Syj0=; b=LpXCjJP0NeTgB4RZPQYaDz/YoIZR6cVF8ifNRyCNt18djPAGUwLtHLy25DaZTC62bM ShbDdz7pdcEi+7DKtLk9KCZNio6/W+xDoKopUQhIomfP51TkU82e5+fnLjO9RnEu7SC3 2qx0+a0CZ+j8TiH6IrY8LC3gxLhU/BeShsc1o= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :references; b=a0CiR4SAf9bP6EhkCzjwJwnVjr/N8+s57vpBZveDJ2ncQCVVGVRXfJ5y3qLocAKoqv 34NLOk6CD4oA1yhCRkHcpsvwxLyYe+gRhsxcUNMVnHvqtH/SMxtTka/u4z8Ozl0mHBrb J3MauJABCs9Vs/VY4GH+GKzrcBry8qXfQpR+w= Received: by 10.114.95.1 with SMTP id s1mr5920121wab.221.1214409198564; Wed, 25 Jun 2008 08:53:18 -0700 (PDT) Received: by 10.114.180.17 with HTTP; Wed, 25 Jun 2008 08:53:18 -0700 (PDT) Message-ID: Date: Wed, 25 Jun 2008 09:53:18 -0600 From: "Scott Marlowe" To: "Adrian Moisey" Subject: Re: Hardware vs Software RAID Cc: pgsql-performance@postgresql.org In-Reply-To: <48622660.4050403@careerjunction.co.za> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <48622660.4050403@careerjunction.co.za> X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200806/143 X-Sequence-Number: 30493 On Wed, Jun 25, 2008 at 5:05 AM, Adrian Moisey wrote: > Hi > > Has anyone done some benchmarks between hardware RAID vs Linux MD software > RAID? > > I'm keen to know the result. I've had good performance from sw RAID-10 in later kernels, especially if it was handling a mostly read type load, like a reporting server. The problem with hw RAID is that the actual performance delivered doesn't always match up to the promise, due to issues like driver bugs, mediocre implementations, etc. Years ago when the first megaraid v2 drivers were coming out they were pretty buggy. Once a stable driver was out they worked quite well. I'm currently having a problem with a "well known very large servermanufacturer who shall remain unnamed" and their semi-custom RAID controller firmware not getting along with the driver for ubuntu. The machine we're ordering to replace it will have a much beefier RAID controller with a better driver / OS match and I expect better behavior from that setup.