From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: XP guests sluggish after around 1 week of uptime Date: Mon, 19 Jan 2009 14:46:12 +0200 Message-ID: <49747614.4010403@redhat.com> References: <496B4757.1090207@redhat.com> <496C5EDD.9000901@redhat.com> <49746CA7.3000907@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: KVM list To: jmandawg Return-path: Received: from mx2.redhat.com ([66.187.237.31]:54443 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758984AbZASMqP (ORCPT ); Mon, 19 Jan 2009 07:46:15 -0500 In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: (re-add kvm@vger) jmandawg wrote: >> -----Original Message----- >> From: Avi Kivity [mailto:avi@redhat.com] >> Sent: Monday, January 19, 2009 7:06 AM >> To: jmandawg >> Cc: kvm@vger.kernel.org >> Subject: Re: XP guests sluggish after around 1 week of uptime >> >> There is a lot of wait time (last column, wrapped around to the first in >> your output). Not a lot of real I/O though. Can you describe your I/O >> subsystem? Are you using NFS? >> >> > > >> What does 'top' show for the guests? I'm interested in qemu's VIRT and RES >> > columns. > >> Also, 'vmstat 1' on host and guest while slow copying is happening. >> > > > I'm using EXT3 on LVM on top of RAID 5. I can try moving one of the guest > images to a different disk without the RAID 5 if you think that would help. > Software RAID or hardware RAID? I think the root cause is the RAID here, not kvm. Some suggestions: - use the raw format directly on top of LVM. That is, use -drive file=/dev/volgroup/logvol. - if you use the raw format, disable disk caching: -drive file=/dev/volgroup/logvol,cache=off - try non-RAID5 storage To migrate your volumes, use qemu-img convert /path/to/image.qcow -O raw /dev/volgroup/logvol Be sure to size the volume appropriately (same size as the virtual image). > I just restarted the host machine yesterday, so the file copies are not > running as slow as before, but still slow. > Here is the current output of top during a file copy: > > top - 07:31:53 up 18:09, 4 users, load average: 0.74, 0.57, 0.46 > Tasks: 157 total, 1 running, 156 sleeping, 0 stopped, 0 zombie > Cpu(s): 6.7%us, 12.7%sy, 0.0%ni, 59.6%id, 19.9%wa, 0.0%hi, 1.0%si, > 0.0%st > Mem: 8190236k total, 8141100k used, 49136k free, 1246732k buffers > Swap: 8388600k total, 228k used, 8388372k free, 2418596k cached > > PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND > 5945 root 20 0 2131m 2.0g 1924 D 13 25.8 44:15.71 kvm > S=D: waiting for disk. Low cpu usage as expected. > > Here is the current output of vmstat 1 during a file copy: > procs -----------memory---------- ---swap-- -----io---- -system-- > ----cpu---- > r b swpd free buff cache si so bi bo in cs us sy id > wa > 0 1 228 46008 1210608 2466132 0 0 2308 8024 2695 13290 7 17 > 63 13 > This seems fine if a bit low. You'll get better numbers sitting directly atop LVM. -- error compiling committee.c: too many arguments to function