On Tue, Apr 17, 2012 at 04:23:04PM +0800, William Herry wrote: > Hi all > > we plan to use openstack on our production, > we are not sure which disk type will be the better choice > > I did a little test on qcow2 and it's performance looks good when I use > cache=writeback > > can some one give us some advice, or some article, > cause for such common topic must be discussed before
Raw files or block devices will always have some performance advantage over qcow2, though I don't have figures to tell you just how much of a difference it will be. The performance gap is certainly much smaller than it used to be a few years back. The more important question is probably, do you actually need any of the other features that qcow2 gives over raw ? eg internal snapshots, external backing files, encryption, compression, etc ? If you don't need any of these features, then there is no real point in choosing to use qcow2 over raw. REgards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :| _______________________________________________ Mailing list: https://launchpad.net/~openstack Post to : openstack@lists.launchpad.net Unsubscribe : https://launchpad.net/~openstack More help : https://help.launchpad.net/ListHelp
