Re: File Formats

[Dominic Raferd]

On 27/03/2021 07:29, reg.rdiff_backup@excel4x.com wrote:
> On 25.03.2021 09:29, reg.rdiff_backup@excel4x.com wrote:
> > > I just heard about rdiff-backup and I'm planning how to
> > configure it.
> > > The documentation says:
> > > "Earlier states of your files are saved just by 1) keeping
> > a copy of
> > > them,
> > > 2) in diff form as produced by rdiff, or 3) as a gzipped
> > version of 1 or 2."
> > > I see the --no-compression option to disable compression.
> > However I do
> > > not see an option to produce copies of older files vs.
> > storing them in
> > > rdiff format. How is the file format for older files controlled?
> > >
> > > Thanks much!
> > Hello and welcome!
> >
> > I don't think it matters to you - it should be just a
> > description of how rdiff-backup handles file history internally.
> >
> > --no-compression should disable compression of older files
> > when a newer snapshot is created. It's sometimes useful to
> > disable compression because gzip is rather CPU hungry and
> > depending on files it can make the backup take a long time.

> Actually it does matter to me. I do not want to rely on a chain of reverse
> diffs to reconstruct important files. My concern is that a disk error could
> render reconstruction impossible. I would like every version to remain as a
> self-contained snapshot. So, I want to use compression and snapshots only.
>
> The documentation says that earlier states of files can be saved as copies
> or diffs. However there does not appear to be a run-time option to create
> copies. I looked at the python code in increment.py and it does not seem to
> have an option to create copies for regular files.
>
> Is there a way to force rdiff-backup to always create copies of earlier file
> versions?
You can verify rdiff-backup repositories as a way to give you 
confidence. My approach to guard against disk error is to take a 
straightforward (rsync) backup of my rdiff-backup repositories but only 
after they are verified.

But if you insist on atomic backups-in-time then maybe something like 
rsnapshot would be a better tool for you.

BTW the style here is to bottom-post.