Re: [Duplicity-talk] Feature request/discussion: Store identical files only once

[Olivier Croquette]

Peter Schuller wrote, On 25/06/08 8:12:
> I considered in the past implementing an exclusively hash-based backup where 
> the backup store would just be a refcounted set of checksum->content 
> mappings, and each backup set a tree of meta-data with checksums.

I was thinking about that too.

> I generally like the idea. The problem I see is security.

I see another problem:

1) either you pack your backed up files in archives just like duplicity 
does, and then you can't delete an archive as long as it contains at 
least one file which is still referenced

2) or you have one backup file for each original file, which causes an 
information leak (gives much more information to an attacker about your 
backup), and also causes performance issues when backuping many files 
(eg. full system backup).

I would go for 1), but it requires to address the mentioned issue with 
still referenced files...