Re: rsync like restore

[Mike Kallies <mike.kallies@gmail.com>]

On Mon, Dec 16, 2013 at 11:55 AM, Colin Percival <cperciva@tarsnap.com> wrote:
> On 12/16/13 02:49, Mike Kallies wrote:
>> For testing, we'd like to do a weekly automated restore on our standby
>> hardware.  The ideal way to do this would be to do an rsync-like
>> restore.
>
> Tarsnap really isn't designed for that... :-/
>
>> [snip]
>> An rsync-like restore could greatly simplify this kind of test.  Is
>> there such a feature?  Is there a different method which people use to
>> test their backups which I'm overlooking?
>
> The closest you can get right now is the --keep-newer-files option (which
> is actually "keep files which are not older") but that would still download
> the entire contents of any files which have changed at all.
>
> I do have an idea for "tarsnap -x --sync" functionality which would reuse
> the deduplication mechanism to identify parts of an existing file so that
> they would not need to be downloaded, but that's not going to happen in
> the near future.

Hello Colin,

Thanks for the tip, was just taking some time to think about the answer.

The --keep-newer-files would mostly do what we need. One exception
though I think are deletions.  Over time they would pile up on the
local target and create some retention issues.

Like you say, not a current design goal for Tarsnap.  I think I can
come up with some programmatic stuff to solve our specific issue.
It's pretty minor.

Great software, thanks again for your help... and Seasons Greetings
and all that!


-Mike