Re: [rdiff-backup-users] delete initial mirror

[R. David Murray]

On Wed, 21 Oct 2009 at 20:54, Alex Samad wrote:
> On Wed, Oct 21, 2009 at 12:56:12AM -0700, plug bert wrote:
> > Hello All,
> >
> >   Is it possible to delete the initial mirror made by rdiff-backup after an 
> > incremental backup is made?
> >
> >
> >   We're looking into ways of performing incremental backups for mbox-style 
> > mailboxes; is this setup possible:
> >
> > Sunday: make an initial mirror
> > Monday - Saturday: schedule incremental backup, *delete* initial mirror
> >
> > Sunday: make initial mirror(i.e. reformat the mirror drive, start from scratch)
> >
> > Monday - Saturday : incremental backup again
> >
> >
> >     Let's say someone deleted a file on Wednesday; *without* the initial 
> > mirror, is it possible to restore the file?
>
> i think you can use remove older than 7B - mean delete anything older
> than 7 runs or 7D for delate any info older than 7 days.
>
> Not sure if rdiff-backup has the concept of full / incremental -
> although it incrementally updates the backup.

As I understand things, and assuming I understand your goals,
Alex is correct here.  If your goal is to always have a valid
backup, but to not keep data around that is older than a week
because of storage concerns, then what you want to do with
rdiff-backup is make an initial backup, and then after every
daily incremental backup, do an rdiff-backup --remove-older-than 7d
on your backup tree.

rdiff-backup keeps the backup tree in sync with the current
tree, and maintains _older_ revisions by using reverse diffs
(as someone else pointed out).  So by using this scheme you
will always have a current complete backup, and you will also
always have the last seven days of changes.  So if someone
deletes a file on Wednesday, it will remain available for
restore until the following Wednesday.

--David