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 o9RA5F5s156380 for ; Wed, 27 Oct 2010 05:05:15 -0500 Received: from smtp4-g21.free.fr (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id C7AFB1363F28 for ; Wed, 27 Oct 2010 03:22:08 -0700 (PDT) Received: from smtp4-g21.free.fr (smtp4-g21.free.fr [212.27.42.4]) by cuda.sgi.com with ESMTP id WyYaK8zqq2RQmOUg for ; Wed, 27 Oct 2010 03:22:08 -0700 (PDT) Date: Wed, 27 Oct 2010 12:06:28 +0200 From: Emmanuel Florac Subject: Re: Pid: 8345, comm: rsync Not tainted 2.6.32.22intel #1 Message-ID: <20101027120628.7b4b2e20@harpe.intellique.com> In-Reply-To: <4CC7CDF6.3080405@profihost.ag> References: <4CC67450.9020602@profihost.ag> <4CC6B56B.7020007@profihost.ag> <20101026132505.6af29d5d@harpe.intellique.com> <201010270124.44846@zmi.at> <20101027080454.31a59a3c@galadriel.home> <4CC7CDF6.3080405@profihost.ag> Mime-Version: 1.0 List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: Stefan Priebe - Profihost AG Cc: Michael Monnerie , xfs@oss.sgi.com Le Wed, 27 Oct 2010 09:00:06 +0200 Stefan Priebe - Profihost AG =E9crivait: > So what values do you recommand in general for iSCSI on Serverside > and which values on iSCSI client side? > = Depends upon the hardware. nr_requests should be 512 for 3Ware cards, 256 to 1024 for other controllers (always more than the default 128 anyway). = Same rule goes for read-ahead; however many RAID controllers (Areca, Adaptec) "cheat" and do read-ahead optimisation by themselves (which may harm random access). The default read-ahead value (256) was OK for obsolete ATA drives with a few KB of cache; nowadays all drives have 32 or 64 MB, and controllers 512 MB to several GB, so more read-ahead can do no harm but fill the cache up. I often go up to 65536 or 131072 sectors (for 24 or 48 drives arrays). Keep in mind that this is sequentail-raid optimisation; random access (such as VM work) may give better result with lower read-ahead values. Benchmarking your application is king here. Just for information : I currently run some servers with kernel 2.6.22.18 (march 2008) and 3Ware firmware 4.10.0.7, so upgrading your 2.6.23 system should be perfectly safe from a driver compatibility point of view. -- = ------------------------------------------------------------------------ Emmanuel Florac | Direction technique | Intellique | | +33 1 78 94 84 02 ------------------------------------------------------------------------ _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs