cy...@suse.com writes: > Set NOCOW flag to newly created images to solve performance issues on btrfs. > > Btrfs has terrible performance when hosting VM images, even more when the > guest > in those VM are also using btrfs as file system. One way to mitigate this bad > performance is to turn off COW attributes on VM files (since having copy on > write for this kind of data is not useful). <snip>
It's been a while since I had to mess with this performance mystery but I recall you also need to ensure the partition needs to be mounted with the nodatacow mount option. Unless this has changed we should probably warn the user about that. -- Alex Bennée
