[comp.sources.wanted] Backup

miller@cpsvax.cps.msu.edu (Joseph M Miller) (05/27/90)

	I am interested in source/csh/sh code that can be used to automatically
   keep a copy of a directory subtree on another local unix machine.  I
   have a few directories of critical information that I want to be the
   same on several machines (failsafe/redundancy issue).

	For example, when I make a change to a file in a mirrored directory 
   on machine A:,  I would like some cron job running every hour or so to 
   reflect changes made to this subdirectory automatically to a similar 
   subdirectory on machine B:.  Only the files that have changed since it 
   last ran should be copied.  Ideally, if I made a change to a file on 
   machine B: it would be copied to A: (but this is not absolutely necessary
    - a master slave type backup would be sufficient).

	I could do a tar cf - . | rsh B "cd rootofsubtree; tar xfBp -"
   occaisionally (daily ?) to perform such a mirror imaging at the expense
   of slowing down the local network a bit, but I would prefer a more
   elegant solution.  Ideally, a package would only copy a file from machine
   A to machine B if the date of the file on machine B was older by say
   10 minutes or so (safety margine).

	Any hints on where to find such software would be greatly
   appreciated.  Either email or post suggestions as you see fit.


							Thanks - Joe
						miller@cpsvax.cps.msu.edu