Encrypted partition backups.

[Roberto Ragusa]

Robin Laing wrote:
> Is there a tool that allows partition backups of only the changes as
> with incremental backups?  Do we just have to clone the partition and
> make copies of that each time?

It is not clear if the backupper is trusted or not and if the disks are
mounted or not.

If the backup is network based, rsync could avoid the transmission of
the unchanged part of hte encrypted partition (better with --inplace).

But having 3 backups of a 100GB partition in a 120GB backup disk
is not as easy as it would with unencrypted files and smart use of
hardlinks.
Something could be done by splitting the partition in pieces
(for example of 4MB) and storing backups of the pieces.
In that way pieces unchanged in the 3 backups could be hardlinked.
This method could be done with a little script (dd skip= count= ,
md5sum, cp, ln).
It would be basically reimplementing the snapshot feature of the device
mapper.

Best regards.
-- 
   Roberto Ragusa    mail at robertoragusa.it