Am Mittwoch, 20. März 2013 schrieb David Lang: > On Wed, 20 Mar 2013, Martin Steigerwald wrote: > > Am Dienstag, 29. Januar 2013 schrieb Daniel Phillips: > >> On Mon, Jan 28, 2013 at 5:40 PM, Theodore Ts'o <tytso@xxxxxxx> wrote: > >>> On Mon, Jan 28, 2013 at 04:20:11PM -0800, Darrick J. Wong wrote: > >>>> On Mon, Jan 28, 2013 at 03:27:38PM -0800, David Lang wrote: > >>>>> The situation I'm thinking of is when dealing with VMs, you make a > >>>>> filesystem image once and clone it multiple times. Won't that end > >>>>> up with the same UUID in the superblock? > >>>> > >>>> Yes, but one ought to be able to change the UUID a la tune2fs > >>>> -U. Even still... so long as the VM images have a different UUID > >>>> than the fs that they live on, it ought to be fine. > >>> > >>> ... and this is something most system administrators should be > >>> familiar with. For example, it's one of those things that Norton > >>> Ghost when makes file system image copes (the equivalent of "tune2fs > >>> -U random /dev/XXX") > >> > >> Hmm, maybe I missed something but it does not seem like a good idea > >> to use the volume UID itself to generate unique-per-volume metadata > >> hashes, if users expect to be able to change it. All the metadata > >> hashes would need to be changed. > > > > I believe that is what BTRFS is doing. > > > > And yes, AFAIK there is no easy way to change the UUID of a BTRFS > > filesystems after it was created. > > In a world where systems are cloned, and many VMs are started from one > master copy of a filesystem, a UUID is about as far from unique as > anything you can generate. > > BTRFS may have this problem, but why should Tux3 copy the problem? I didn´t ask for copying that behavior. I just mentioned it :) -- Martin 'Helios' Steigerwald - http://www.Lichtvoll.de GPG: 03B0 0D6C 0040 0710 4AFA B82F 991B EAAC A599 84C7 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
