Re: [rdiff-backup-users] rdiff-backup problems (FC4 -> VFAT)

[Wiebe Cazemier]

Ben Escoto wrote:
> That was the old default, the current default is the preserve unames
> and gnames (not uids and gids) so restoring to a new system should
> work.  

I know, I liked the old way better :( The old way isn't possible anymore, which 
I think it should be. Let me explain.

You use rdiff-backup to backup the entire system (putting aside my concerns 
about possible mtime presevervations of the package manager, which I described 
above). Your HD crashed, and you're going to restore your backup. To do so, you 
boot into Knoppix, somehow install rdiff-backup, and restore the backup to a new 
HD. Rdiff-backup will match the UID's and GID's of the filesystem to the 
/etc/passwd and /etc/group of Knoppix. Let's consider a file which belonged to 
"postmaster" on the old sytem, and which had UID 14. If "postmaster" has user ID 
15 on Knoppix, the restored file will have UID 15. But, because on the system 
that's being restored, UID 15 is "man", the file which should belong to 
"postmaster", now belongs to "man" (after booting the restored system of course).

> You can modify this behavior with the --user-mapping-file or
> --group-mapping-file switches.

The solve my dillema, an option like --preserve-numerical-ids should be 
available. Matching against names is perfect when restoring parts of a system, 
but not an entire system. It should restore the filesystem as it was, and not 
get too smart.