From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda3.sgi.com [192.48.176.15]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id p6KN1VtB252284 for ; Wed, 20 Jul 2011 18:01:32 -0500 Received: from ipmail07.adl2.internode.on.net (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 5948518093A1 for ; Wed, 20 Jul 2011 16:01:29 -0700 (PDT) Received: from ipmail07.adl2.internode.on.net (ipmail07.adl2.internode.on.net [150.101.137.131]) by cuda.sgi.com with ESMTP id X4whAWwBd5rpJcka for ; Wed, 20 Jul 2011 16:01:29 -0700 (PDT) Date: Thu, 21 Jul 2011 09:01:26 +1000 From: Dave Chinner Subject: Re: 30 TB RAID6 + XFS slow write performance Message-ID: <20110720230126.GH9359@dastard> References: <4E24907F.6020903@johnbokma.com> <20110720064419.GG9359@dastard> <4E26C5C5.1090802@hardwarefreak.com> <201107201604.33419@zmi.at> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <201107201604.33419@zmi.at> 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: Michael Monnerie Cc: John Bokma , Stan Hoeppner , xfs@oss.sgi.com On Wed, Jul 20, 2011 at 04:04:31PM +0200, Michael Monnerie wrote: > On Mittwoch, 20. Juli 2011 Stan Hoeppner wrote: > > I thought this was packing multiple small files into > > a single stripe write, which you just explained XFS does not do. > > This is interesting, I jump in here. Does that mean that if I have a XFS > volume with sw=14,su=64k (14*64=896KiB) that when I write 10 small files > in the same dir with 2KB each, each file would be placed at a 896KiB > boundary? No, they'll get sunit aligned but default, which would be on 64k boundaries. > That way, all stripes of a 1GB partition would be full when > there are roughly 1170 files (1170*896KiB ~ 1GB). What would happen when > I create other files - is XFS "full" then, or would it start using sub- > stripes? If sub-stripes, would they start at su (=64KiB) distances, or > at single block (e.g. 4KiB) distances? It starts packing files tightly into remaining free space when no free aligned extents are availble for allocation in the AG. Cheers, Dave. -- Dave Chinner david@fromorbit.com _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs