Just to be clear on the original question, xfs_freeze is not an lvm command. It's part of the xfs package xfsprogs.
----------------------------------------------------- toby bluhm philips medical systems, cleveland ohio [EMAIL PROTECTED] 440-483-5323 [EMAIL PROTECTED] wrote on 07/10/2006 03:10:52 AM: > On 2006-07-08 12:44, Josef Wolf wrote: > > On Fri, Jul 07, 2006 at 11:13:44PM +0200, Paul Bijnens wrote: > > > >> There are two approaches (maybe even many more -- I'm not the > >> specialist here). > >> > >> One approach is to let the snapshot mechanism understand the filesystem > >> and work on that level. That is how xfs and solaris ufs snapshots seem > >> to work. > >> > >> The other approach is a layer deeper: on the logical volume manager. > >> This implementation is not interested in where the inodes are located > >> or how directories and datablocks are layed out on disk. The LVM just > >> manages large blocks. The LVM2 snapshots in linux work on this layer. > > > > If the snapshot is on the driver layer, there is no way to ensure that > > the snapshot is consistent? Thus the snapshot would look like the power > > switch was turned off at that moment. Without journalling, data loss can > > be expected. I would rather not base my backups on such a mechanism... > > > >> Using method 1, you can probably get more optimized (quicker, using less > >> diskspace). Using method 2 is more general, and is is independent of > >> the filesystems on it. In my test setup I even managed to make a > >> snapshots of a vfat filesystem. > > > > I don't think vfat have journalling. > > > Yes, indeed! You better have journalling to be really useful. > > But after sync and with a "quiet" filesystem (if really necessary > unmount it) you *can* make a snapshot. > > It's not that snapshotting vfat is elegant, but it shows the power of > doing snapshots a on the blocklevel instead of on the filesystem level. > > > -- > Paul Bijnens, xplanation Technology Services Tel +32 16 397.511 > Technologielaan 21 bus 2, B-3001 Leuven, BELGIUM Fax +32 16 397.512 > http://www.xplanation.com/ email: [EMAIL PROTECTED] > *********************************************************************** > * I think I've got the hang of it now: exit, ^D, ^C, ^\, ^Z, ^Q, ^^, * > * F6, quit, ZZ, :q, :q!, M-Z, ^X^C, logoff, logout, close, bye, /bye, * > * stop, end, F3, ~., ^]c, +++ ATH, disconnect, halt, abort, hangup, * > * PF4, F20, ^X^X, :D::D, KJOB, F14-f-e, F8-e, kill -1 $$, shutdown, * > * init 0, kill -9 1, Alt-F4, Ctrl-Alt-Del, AltGr-NumLock, Stop-A, ... * > * ... "Are you sure?" ... YES ... Phew ... I'm out * > *********************************************************************** >