From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: with ECARTIS (v1.0.0; list xfs); Sun, 23 Mar 2008 21:01:49 -0700 (PDT) Received: from cuda.sgi.com (cuda1.sgi.com [192.48.168.28]) by oss.sgi.com (8.12.11.20060308/8.12.11/SuSE Linux 0.7) with ESMTP id m2O41Xs5012732 for ; Sun, 23 Mar 2008 21:01:35 -0700 Received: from smtp-out03.alice-dsl.net (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 6F168100525C for ; Sun, 23 Mar 2008 21:02:06 -0700 (PDT) Received: from smtp-out03.alice-dsl.net (smtp-out03.alice-dsl.net [88.44.63.5]) by cuda.sgi.com with ESMTP id N5HWIJC5QipyMVxr for ; Sun, 23 Mar 2008 21:02:06 -0700 (PDT) Subject: Re: Poor VMWare disk performance on XFS partition References: <876423.51989.qm@web52006.mail.re2.yahoo.com> <47E6C09E.5030601@sandeen.net> From: Andi Kleen Date: 24 Mar 2008 05:02:04 +0100 In-Reply-To: <47E6C09E.5030601@sandeen.net> Message-ID: <87prtk7osj.fsf@basil.nowhere.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: xfs-bounce@oss.sgi.com Errors-to: xfs-bounce@oss.sgi.com List-Id: xfs To: Eric Sandeen Cc: "Hendrik ." , xfs@oss.sgi.com Eric Sandeen writes: > > What does xfs_bmap and/or filefrag say, is this file indeed very > fragmented? > And is it less so on ext3? If the file is persistent then > preallocating it would probably help. Preallocating would prevent one of the main features of a sparse VM images: starting small and only growing as the virtual machine needs more storage without having to resize the virtual partitions. I remember XFS had a mmap problem a long time ago (in 2.4) which sounded similar (iirc it trickered with samba), but I thought it was long fixed. The problem back then was that page flushing on mmaps didn't get merged due to some unfortunate VM interactions and then thousands of extents got created on flushing a mmap. A lot of extents seems to make XFS slow. -Andi