Re: [rdiff-backup-users] atomic increment files?

[Andrew Ferguson]

On Mar 9, 2009, at 11:56 PM, Marcel (Felix) Giannelia wrote:

> If this operation were used to make backups sparser the farther back  
> in time you go (which seems to be what people on the wiki are  
> after), and rdiff-backup already keeps snapshots every 10 increments  
> or so, maybe just discard the ones that aren't snapshots? And then  
> you might be able to shrink those snapshots by in turn diff'ing some  
> of them with each other, as in:
> Before consolidation: [current mirror] <10 diffs> [snapshot] <10  
> diffs> [snapshot] <10 diffs> <snapshot> <10 diffs>
> becomes: [current mirror] <10 diffs> [snapshot] [snapshot] [snapshot]
> and then: [current mirror] <10 diffs> [snapshot] <2 diffs>


Interesting idea, except that rdiff-backup doesn't make a snapshot  
every 10 backups, it makes a snapshot every 10 times that a file has  
changed.

What people want to be able to do is "delete the backup from 6 days  
ago, preserving the ones from 7 days ago and 5 days ago". At that time  
in the past, file A may be a snapshot, and file B may be a reverse- 
diff. File A is easy to handle (7 days ago becomes a snapshot), but  
File B requires a merge-diff operation.


Andrew