Re: HDD duplication in RH7.3

["Theodore Ts'o" <tytso mit edu>]

On Mon, Sep 02, 2002 at 11:27:50AM +0100, Stephen C. Tweedie wrote:
> 
> Yes --- we don't have the initial blocks in memory in ext3 any more
> than in ext2.
> 
> However, ext3's journaling _does_ mean that it's really easy to
> completely quiesce the filesystem and mark it temporarily clean, so
> the LVM snapshot functionality can do ext3 snapshots which don't
> require any recovery.

As a note, the EVMS snapshot functionality has this capability as
well, with two additional features beyond that of the LVM code:

1) The source filesystem doesn't have to be an LVM volume; it can be a
standard MS-DOS compatible partition.

2) The snapshots can be optionally marked "writeable", so you can
modify the snapshot as well as the source filesystem after creating
the coherent snapshot.

						- Ted