On Mon, Jul 08, 2013 at 04:17:36PM +0200, David Disseldorp wrote:
On Mon, 8 Jul 2013 14:14:19 +0200 David Sterba
wrote: VM and database loads do not play well with the COW mechanism. The NOCOW file attribute (chattr +C) fixed the performance problems with VM images for me and reportedly for others. This comes at a price, the checksums are turned off for the file.
IIUC, that also removes the ability to instantaneously clone VM images using cp --reflink. I'd consider that a pretty severe cost for a workload where Btrfs normally excels.
That's right and more serious than the csums. As a compromise, the vm images may be a mixed set of cow and nocow files, let's say the rootfs is cow-based and data partitions are nocow. david -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-factory+owner@opensuse.org