Re: [rdiff-backup-users] Couple of problems

[Ben Escoto]

On Tue, 16 Sep 2003 09:01:00 +0100 Keith Edmunds <address@hidden> wrote:
> Recently I had a corrupted file on a Linux system - it went to zero
> bytes and the permissions were also zero. No problem: I'll restore it
> from the nightly rdiff-backup...
> 
> The first problem was that I did not know when the file became
> corrupted. I needed a command which would show me all the different
> versions of that particular file which had been backed up, together with
> the size (and the date would be useful too). Unless I've missed
> something there is no such command available in rdiff-backup. I think
> this could be a useful addition.

Well, there is --list-increments, but that won't tell you the
increment sizes.  You can also just

        ls -l <dir>/rdiff-backup-data/increments/.../prefix*

which will give you some information, and perhaps you can tell when
the file was corrupted from the increment sizes.  Unfortunately, the
actual sizes aren't readily available.

> The second problem was more subtle. When I found the problem (yesterday)
> I first changed the permissions on the real file (as opposed to the
> backup version), and when the backup ran last night it failed with
> "permission denied" error on the backup copy of this file. Observation
> 1: could this be a 'soft' error rather than stopping the whole backup?
> Today I tried a "--list-changed-since" of the backup directory and
> received the "Previous backup to xxx seems to have failed. Rerun
> rdiff-backup with --check-destination-dir option to revert directory to
> state before unsuccessful session." So I did that, but _that_ fails with
> "IOError: [Errno 13] Permission denied:
> '/--directory-path--/rdiff-backup.tmp.0'"
> 
> I think I can see what is happening - rdiff-backup wants to change the
> permissions of a file to those which give it no access(!), but how do I
> overcome this? Should I use the --force parameter?

Hmm, are you using 0.12.4?  There was a fix for a permissions error
that may cover this case.  It's strange, that bug was in rdiff-backup
since 0.11.1 probably, but no one mentions it until 0.12.3, when at
least 3 people seem to have run into it.

> In summary, three questions:
> 
> 1. Is there a way to list the history of changes for one given file,
> preferably with file sizes too?

Try, --list-increments, or just 'ls -l' in the increments directory
(the latter is actually more informative in this case).

> 2. If rdiff-backup has a problem backing up one file could it continue
> with the next?

Yes, there was a bug though.

> 3. How do I recover from the situation I'm currently in?

I'm not exactly sure what is going on in your case, but here are some
suggestions:

1.  Try upgrading to 0.12.4 if you haven't already.
2.  Try running as root, which will get you are the permission denied
    errors (the bug fix only affected non-root users where the source
    was root).
3.  Make sure all the increments are readable.  You can change the
    permission of these manually without upsetting rdiff-backup's
    regress mechanism.
4.  Give me a bit more information, like the permissions of the
    relevant increments, and maybe the traceback if rdiff-backup
    fails.  Are all the directories readable?
5.  If you are in a hurry, you can always dispense with rdiff-backup
    and restore the file "manually" by running rdiff repeatedly.


-- 
Ben Escoto

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