From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda1.sgi.com [192.48.157.11]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id n2NG2Ytn168261 for ; Mon, 23 Mar 2009 11:02:54 -0500 Received: from web51309.mail.re2.yahoo.com (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with SMTP id 04CA313BF496 for ; Mon, 23 Mar 2009 09:02:21 -0700 (PDT) Received: from web51309.mail.re2.yahoo.com (web51309.mail.re2.yahoo.com [206.190.38.175]) by cuda.sgi.com with SMTP id QXbwc3H28jenuxHF for ; Mon, 23 Mar 2009 09:02:21 -0700 (PDT) Message-ID: <174852.24274.qm@web51309.mail.re2.yahoo.com> Date: Mon, 23 Mar 2009 09:02:14 -0700 (PDT) From: Jon Hardcastle Subject: Re: How to configure 36 disks ? In-Reply-To: <49C7AC2C.9090307@tmr.com> MIME-Version: 1.0 Reply-To: Jon@eHardcastle.com List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: Raz , Bill Davidsen Cc: linux-fsdevel@vger.kernel.org, Linux RAID Mailing List , "linux-ide@vger.kernel.org" , linux-xfs@oss.sgi.com, linux-aio@kvack.org I'd like to understand how you even go attaching that many devices to a system.. I am 'comparatively' new to this.. and have a 6 raid5 system.. not enterprise.. and i have slammed into case/power/sat slot issues already. What sort of hardware must one use to grow to a 36 array system! ----------------------- N: Jon Hardcastle E: Jon@eHardcastle.com '..Be fearful when others are greedy, and be greedy when others are fearful.' ----------------------- --- On Mon, 23/3/09, Bill Davidsen wrote: > From: Bill Davidsen > Subject: Re: How to configure 36 disks ? > To: "Raz" > Cc: linux-fsdevel@vger.kernel.org, "Linux RAID Mailing List" , linux-xfs@oss.sgi.com, linux-aio@kvack.org, "linux-ide@vger.kernel.org" > Date: Monday, 23 March, 2009, 3:35 PM > Raz wrote: > > Hello > > I need to configure 3xDAS'es, each with 12 disks. > > All three DAS'es are connected to a single > machine. > > I have the following requirements (in this order of > importance) > > from the storage: > > > > 1. redundancy. > > having two disks failing in one raid5 breaks the > entire raid. when > > you have 30TB storage > > it is a disaster. > > > > 2. performance. > > My code eliminates Linux raid5/6 write penalty. I > managed to do by > > manipulating xfs and patching linux raid5 a bit. > > > > 3. modularity ( a "grow" and it will be nice > to have "shrink" ) > > file system and volume must be able to grow. > shrinking is possible > > by unifying multiple file systems > > under unionfs or aufs. > > > > 4. Utilize storage size. > > > > I assume each disk is 1TB. > > > > > ___ snip ___ > > > Any other ideas ? > > Yes, you have the whole solution rotated 90 degrees. > Consider your original solution #2 below... You have no > redundancy if one whole DAS box fails, which is certainly a > possible failure mode. If you put the RAID0 horizontally, > two arrays size six in each DAS, then RAID6 vertically, if > one DAS fails completely you still have a functioning > system, and the failure results for individual drives > remains about the same, while the rebuild time will be > longer. > > Solution #2 > raid0 > DAS1: raid6: D,D,D,D,D,D | > raid6: D,D,D,D,D,D | > | > DAS2: raid6: D,D,D,D,D,D | xfs. > raid6: D,D,D,D,D,D | > | > DAS3: raid6: D,D,D,D,D,D | > raid6: D,D,D,D,D,D | > > > In addition, you can expand this configuration by adding > more DAS units. This addresses several of your goals. > > In practice, just to get faster rebuild as the array gets > larger, I suspect you would find it was worth making the > horizontal arrays RAID5 instead of RAID0, just to minimize > time to full performance. > > -- bill davidsen > CTO TMR Associates, Inc > > "You are disgraced professional losers. And by the > way, give us our money back." > - Representative Earl Pomeroy, Democrat of North Dakota > on the A.I.G. executives who were paid bonuses after a > federal bailout. > > > -- > To unsubscribe from this list: send the line > "unsubscribe linux-raid" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at > http://vger.kernel.org/majordomo-info.html _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs