From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: with ECARTIS (v1.0.0; list xfs); Sun, 23 Mar 2008 13:41:43 -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 m2NKfYlU005596 for ; Sun, 23 Mar 2008 13:41:35 -0700 Received: from sandeen.net (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 2B70C125F1D6 for ; Sun, 23 Mar 2008 13:42:07 -0700 (PDT) Received: from sandeen.net (sandeen.net [209.173.210.139]) by cuda.sgi.com with ESMTP id s7nDfDn5u38qAK9U for ; Sun, 23 Mar 2008 13:42:07 -0700 (PDT) Message-ID: <47E6C09E.5030601@sandeen.net> Date: Sun, 23 Mar 2008 15:42:06 -0500 From: Eric Sandeen MIME-Version: 1.0 Subject: Re: Poor VMWare disk performance on XFS partition References: <876423.51989.qm@web52006.mail.re2.yahoo.com> In-Reply-To: <876423.51989.qm@web52006.mail.re2.yahoo.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: xfs-bounce@oss.sgi.com Errors-to: xfs-bounce@oss.sgi.com List-Id: xfs To: "Hendrik ." Cc: xfs@oss.sgi.com Hendrik . wrote: > I've been converting some of my drives from EXT3 to > XFS a while ago. Now I notice poor disk performance > when using XFS as underlying filesystem for a VMware > virtual drive. I did some experiments and it really > seems to be the XFS filesystem 'trashing' the speed of > a VMware Windows XP guest. > > The first thing that I noticed is that when I shut > down the virtual machine it takes a very long time > after the machine seems to be shut down until the > VMware window becomes responsive again. In the mean > time there is heavy disk I/O. I found out that VMware > seems to write some kind of memory map on the host > hard disk which get heavily fragmented. 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. > The removal of > this file is probably very I/O intensive which causes > the delay. This is very annoying but not really a > problem as it only happens when a virtual machine is > shut down. > > But there seems to be another problem when running the > guest operating system itself. I made two exact copies > of a Windows XP virtual machine on two hard disks of > the same type, size and brand. The first hard disk had > a XFS partition to host the virtual machine, the > seconds harddisk was formatted as EXT3. The XFS > partition has no fragmentation at all thus all files > only consisted of 1 extent. The EXT3 files were a bit > fragmented but this was only marginal (some larger > disk image files consisted of 17 extents where 16 was > optimal, reported by 'filefrag'). I've honestly never used vmware. How many disk image files per guest? You said 2 copies of an XP VM, one on xfs and one on ext3, but then said "EXT3 files" so I'm not sure what the big picture looks like here. If a single guest uses multiple files, can you run xfs_bmap -v on them, it may be that xfs is spreading them out between the AGs, thereby putting them into different regions of the disk. > Then I ran the virtual machines one by one and started > a defragmentation program to cause a lot of I/O on the > guest operating system. Defragmentation of the XP host > running from the EXT3 partition took only 2m36 but the > exact same guest on the XFS partition took 10m5 to > complete. On the EXT3 partition hardly any noise was > heard from the drive heads as if the host operating > system was caching and delaying the I/O operations. On > the XFS host however a lot of noise was heard as if > the harddisk was trashing heavily. Maybe try using seekwatcher to trace/graph IO of the vmware processes to see what's going on? -Eric