<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hi Scott,<div><br></div><div>kvm --version<br>QEMU emulator version 0.13.91 (qemu-kvm-0.14.0-rc1), Copyright (c) 2003-2008 Fabrice Bellard<br><br></div><div>virsh --version<br>0.8.8<br><br></div><div>uname -r</div><div>2.6.35-22-server</div><div><br></div><div>Need any more info?</div><div><br></div><div><div>
<div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div>Met vriendelijke groet,<br><br>Martin van Wilderen<br>Technical Manager</div></div></div>
</div>
<br><div><div>On Mar 26, 2012, at 5:12 PM, Scott Moser wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div>Can you provide information about what version of kvm you're using ?<br>I suspect this is really unrelated to openstack specifically.<br><br>On Mon, 26 Mar 2012, Martin van Wilderen - JDN BV wrote:<br><br><blockquote type="cite">Hi List,<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">I have a question about KVM disk performance. We are using Openstack Nova on three machines. These machines have a SSD drive with a dd write performance of about 130mb/s<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">Within the instance the write performance is down to about 5 mb/s. When using the allocate trick (dd zero to disk before newfs) we get a performance of 20 mb/s.<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">Things a have tried but don't give any extra results are:<br></blockquote><blockquote type="cite">- Settings the disklayout from qcow2 to raw<br></blockquote><blockquote type="cite">- Settings the cache type in libvirt.xml (writeback, writethrough, none)<br></blockquote><blockquote type="cite">- Switching KSM on and off.<br></blockquote><blockquote type="cite">- Tested with different guests OS, Linux, FreeBSD, Windows.<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">Is there someone who had some extra info i can check? Or are there more people with this issue?<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">Snippet from libvirt.xml<br></blockquote><blockquote type="cite"><driver type='qcow2'/ cache='writeback'/><br></blockquote><blockquote type="cite"><source file='/var/lib/nova/instances/instance-00000113/disk'/><br></blockquote><blockquote type="cite"><target dev='vda' bus='virtio'/><br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">Kind regards,<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">Martin<br></blockquote><blockquote type="cite">_______________________________________________<br></blockquote><blockquote type="cite">Mailing list: <a href="https://launchpad.net/~openstack">https://launchpad.net/~openstack</a><br></blockquote><blockquote type="cite">Post to : <a href="mailto:openstack@lists.launchpad.net">openstack@lists.launchpad.net</a><br></blockquote><blockquote type="cite">Unsubscribe : <a href="https://launchpad.net/~openstack">https://launchpad.net/~openstack</a><br></blockquote><blockquote type="cite">More help : <a href="https://help.launchpad.net/ListHelp">https://help.launchpad.net/ListHelp</a><br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite"><br></blockquote></div></blockquote></div><br></div></body></html>