From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keld =?iso-8859-1?Q?J=F8rn?= Simonsen Subject: Re: What's the typical RAID10 setup? Date: Wed, 2 Feb 2011 00:35:20 +0100 Message-ID: <20110201233520.GB26817@www2.open-std.org> References: <4D4718E1.9040607@hardwarefreak.com> <20110131203725.GB2283@www2.open-std.org> <20110131225235.GA11775@www2.open-std.org> <4D4883A3.6030605@hardwarefreak.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <4D4883A3.6030605@hardwarefreak.com> Sender: linux-raid-owner@vger.kernel.org To: Stan Hoeppner Cc: Jon Nelson , David Brown , linux-raid@vger.kernel.org List-Id: linux-raid.ids On Tue, Feb 01, 2011 at 04:05:23PM -0600, Stan Hoeppner wrote: > Jon Nelson put forth on 2/1/2011 7:50 AM: > > > The performance will not be the same because. Whenever possible, md > > reads from the outermost portion of the disk -- theoretically the > > fastest portion of the disk (by 2 or 3 times as much as the inner > > tracks) -- and in this way raid10,f2 can actually be faster than > > raid0. > > Faster in what regard? I assume you mean purely sequential read, and not random > IOPS. The access patterns of the vast majority of workloads are random, so I > don't see much real world benefit, if what you say is correct. This might > benefit MythTV or similar niche streaming apps. It is mostly interesting for workstations, where one user is the sole user of the system But it is also interesting for a server, where the client is interested in the completion time for a single request. The faster processing of a sequential reads is significant, as far as I can tell. Best regards keld