Re: [rdiff-backup-users] Changing ownership of files in archive

[Robert Nichols]

On 10/24/2011 02:47 PM, zero wrote:
> Robert Nichols wrote:
> Can't this be handled with the --user-mapping-file and
> --group-mapping-file options described in the "USERS AND GROUPS" section of
> the manual? If not, it would help if you would describe what you have tried
> and what the result or specific error was. Just saying "cannot get
> rdiff-backup to work" isn't terribly useful.
>
> When moving the files to a new computer, the owner changed for some reason to
> one that doesn't exist on the new computer. When I try to run rdiff-backup -l
> I get this error: Fatal Error: Bad directory stuff.current.bak.admin.num. It
> doesn't appear to be an rdiff-backup destination dir
>
> This is easily solved by chowning the files in the backup directory to user
> that exist on the new computer. This removes the error message. I realize
> that the uid and gid and username recorded in the rdiff-backup-data folder is
> now inconsistent with the current data. Despite this everything seems to work
> fine. I can restore files. The only thing is that when I restore files and
> then compare the restored files with the backup directory I see that the
> metadata has changed. So I just backup the newly restored data again to
> update the records in rdiff-backup directory. But is there a possibility that
> this inconsistency of metadata in archive can make it impossible to get back
> old files somewhere down the road?

I can't figure out what could be causing the problem you are seeing.  I
have an external drive containing backup sets from several different
systems, and I have no trouble at all listing and restoring files for
user IDs that don't exist on the current system.  If I try to do that
from a non-root UID that doesn't have permission to access some of those
directories on the backup, I get an explicit "permission denied"
message.  The only way I get the messages you are seeing is when I
deliberately give rdiff-backup the name of a directory that doesn't
exist or indeed is not part of an rdiff-backup set.

Changing the ownership of files in the mirror _should_ be harmless.
Indeed, rdiff-backup can store its backups on file systems that don't
support Unix-like ownership and permissions.  But, that change is
certainly not something I have tried, so I can't be sure that there are
no obscure implications.

--
Bob Nichols     "NOSPAM" is really part of my email address.
                Do NOT delete it.