Hi Scott, kvm --version QEMU emulator version 0.13.91 (qemu-kvm-0.14.0-rc1), Copyright (c) 2003-2008 Fabrice Bellard
virsh --version 0.8.8 uname -r 2.6.35-22-server Need any more info? Met vriendelijke groet, Martin van Wilderen Technical Manager On Mar 26, 2012, at 5:12 PM, Scott Moser wrote: > Can you provide information about what version of kvm you're using ? > I suspect this is really unrelated to openstack specifically. > > On Mon, 26 Mar 2012, Martin van Wilderen - JDN BV wrote: > >> Hi List, >> >> 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 >> >> 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. >> >> Things a have tried but don't give any extra results are: >> - Settings the disklayout from qcow2 to raw >> - Settings the cache type in libvirt.xml (writeback, writethrough, none) >> - Switching KSM on and off. >> - Tested with different guests OS, Linux, FreeBSD, Windows. >> >> Is there someone who had some extra info i can check? Or are there more >> people with this issue? >> >> Snippet from libvirt.xml >> <driver type='qcow2'/ cache='writeback'/> >> <source file='/var/lib/nova/instances/instance-00000113/disk'/> >> <target dev='vda' bus='virtio'/> >> >> Kind regards, >> >> Martin >> _______________________________________________ >> Mailing list: https://launchpad.net/~openstack >> Post to : [email protected] >> Unsubscribe : https://launchpad.net/~openstack >> More help : https://help.launchpad.net/ListHelp >> >>
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