On Thu, Oct 06, 2011 at 10:26:40PM +1100, Russell Coker wrote:
Why would there be any connection between VM technology and filesystem unless you use VM specific COW systems?
There isn't, particularly. but being able to create a named zvol of any size from your existing zpool is convenient. as is being able to instantly snapshot and/or clone the zvol (havent tested this, but AIUI you can even clone a zvol while the VM is running...which beats the hell out of having to shutdown a running VM running from a disk image just so you can clone it). zfs & zvol compression is nice too. add to that ZFS' built-in support for NFS & iscsi exports and you've got something extremely useful for virtualisation.
ZFS beats XFS in your tests for KVM, why wouldn't it beat XFS for every VM?
when did i say it wouldn't? what i said was: "kvm works really nicely with ZFS ZVOLs too - haven't done any performance tests vs LVM, but it flies compared to disk image files on xfs." no mention of other VMs & ZFS at all. I can't think of any reason why Xen or VirtualBox or VMWare or any similar virtualisation system wouldn't benefit from ZFS in the same way that KVM would. They work well with LVM, so they'll probably work well with ZFS. Even container style VMs like vserver would benefit from being on a zfs filesystem (as opposed to a zfs zvol) if, e.g., you had a nice fast SSD caching it. and (if you have enough RAM and/or SSD cache) ZFS' online de-duping would be useful. solaris zones have been running on zfs for years. craig -- craig sanders <cas@taz.net.au> BOFH excuse #285: Telecommunications is upgrading.