From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: with ECARTIS (v1.0.0; list xfs); Tue, 25 Sep 2007 06:09:53 -0700 (PDT) Received: from cernmxlb.cern.ch (cernmx07.cern.ch [137.138.166.171]) by oss.sgi.com (8.12.10/8.12.10/SuSE Linux 0.7) with ESMTP id l8PD9iQ3019024 for ; Tue, 25 Sep 2007 06:09:48 -0700 Date: Tue, 25 Sep 2007 14:57:33 +0200 From: KELEMEN Peter Subject: Re: mkfs options for a 16x hw raid5 and xfs (mostly large files) Message-ID: <20070925125733.GA20873@luba.cern.ch> References: <20070923093841.GH19983@p15145560.pureserver.info> <20070924173155.GI19983@p15145560.pureserver.info> <20070924203958.GA4082@p15145560.pureserver.info> <20070924213358.GB4082@p15145560.pureserver.info> <20070924215223.GC4082@p15145560.pureserver.info> <20070925123501.GA20499@p15145560.pureserver.info> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20070925123501.GA20499@p15145560.pureserver.info> Sender: xfs-bounce@oss.sgi.com Errors-to: xfs-bounce@oss.sgi.com List-Id: xfs To: linux-xfs@oss.sgi.com * Ralf Gross (ralf-lists@ralfgross.de) [20070925 14:35]: > There is a second RAID device attached to the server (24x > RAID5). The numbers I get from this device are a bit worse than > the 16x RAID 5 numbers (150MB/s read with dd). You are expecting 24 spindles to align up when you have a write request, which has to be 23*chunksize bytes in order to avoid RMW. Additionally, your array is so big that you're very likely to hit another error while rebuilding. Chop up your monster RAID5 array into smaller arrays and stripe across them. Even better, consider RAID10. Peter -- .+'''+. .+'''+. .+'''+. .+'''+. .+'' Kelemen Péter / \ / \ Peter.Kelemen@cern.ch .+' `+...+' `+...+' `+...+' `+...+'