[rdiff-backup-users] instrument data backup

[Z F]

Dear rdiff-backup users


I have a question and thought you might  help me.

I need to backup data from a scientific instrument. The problem is that the 
instrument has limited space, so 

data has to be moved from the instrument onto other drive. From time to time, 
the old data needs to be copied
back to the instrument. Rdiff-backup is handy because regular "cp" command will 
restore the latest version of the datafile.
Thus users can be given read-access to the backup and they can restore data 
they need by themselves.


The "problem" is that if the file is deleted from the source it will no longer 
be available in the "mirror mode". The file
is still there in the backups, but now hidden and a regular user cannot find it 
by looking at the "backup/destination" folder.
I cannot expect the users to be able to do "restore process by themselves"


Is there a mode of rdiff-backup operation which would allow "mirror with 
memory" that is, to tell the program not to 

delete the file in the mirror, even though it was deleted in the source?


If rdiff-backup cannot do it, is there other software which will be perform 
this function?

Thank you very much for your help

ZF