[linux-lvm] Block-Level Backup

[Bill Rugolsky Jr.]

On Thu, Aug 07, 2003 at 03:44:51PM +0200, Herbert Pötzl 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.

For archival storage, I've lately become enamored of hashed-indexing
as used in Plan 9's Venti (for a single server target) or the various
distributed-hash systems (Chord, etc.) for distributed, replicated
storage.

Regards,

	Bill Rugolsky