From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stan Hoeppner Subject: Re: Linux MD? Or an H710p? Date: Tue, 22 Oct 2013 11:56:49 -0500 Message-ID: <5266AE51.4050501@hardwarefreak.com> References: <526328AE.2020908@gmail.com> <21093.14265.261728.755087@quad.stoffel.home> <5265C89A.4000908@gmail.com> <52662849.1080003@hesbynett.no> Reply-To: stan@hardwarefreak.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <52662849.1080003@hesbynett.no> Sender: linux-raid-owner@vger.kernel.org To: David Brown , Steve Bergman Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On 10/22/2013 2:24 AM, David Brown wrote: > On 22/10/13 02:36, Steve Bergman wrote: > > > >> But hey, this is going to be a very nice opportunity for observing XFS's >> savvy with parallel i/o. > > You mentioned using a 6-drive RAID10 in your first email, with XFS on > top of that. Stan is the expert here, but my understanding is that you > should go for three 2-drive RAID1 pairs, and then use an md linear > "raid" for these pairs and put XFS on top of that in order to get the > full benefits of XFS parallelism. XFS on a concatenation, which is what you described above, is a very workload specific storage architecture. It is not a general use architecture, and almost never good for database workloads. Here most of the data is stored in a single file or a small set of files, in a single directory. With such a DB workload and 3 concatenated mirrors, only 1/3rd of the spindles would see the vast majority of the IO. -- Stan