Re: [linux-lvm] Block-Level Backup

[Joe Thornber <thornber sistina com>]

On Thu, Aug 07, 2003 at 11:11:27AM -0400, Bill Rugolsky Jr. wrote:
> On Thu, Aug 07, 2003 at 03:44:51PM +0200, Herbert P?tzl wrote:
> > anyway, as pointed out in another response, there is
> > no good way, at least none I know of, to find the
> > blocks changed since the last backup ...
>  
> The DM snapshot target already keeps track of which blocks have
> been written.  For incremental backup, we really only need
> to know the block numbers.  Why not a new block-meta-data-only
> snapshot target that just records block numbers?  That
> should have *much* lower overhead and consume insignificant
> disk space.

This scheme only works if you don't use the device while you are
taking an incremental backup.  I think the real solution will be based
around snapshots.

- Joe