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
tobias.bluhm AT philips DOT com
440-483-5323
owner-amanda-users AT amanda DOT org 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: Paul.Bijnens AT xplanation DOT com
> ***********************************************************************
> * 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 *
> ***********************************************************************
>
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