[BackupPC-users] On-demand backups of laptops

[Stephen J. <st...@ph...>]

Hi,

I needed a way for to conveniently backup my users' laptops. Some of these 
are rarely, if ever, on our LAN. So, I implemented an on-demand backup 
solution using Unison (rsync like directory sync util with gui) and 
BackupPC.

    laptop  ---------> "cache" disk  -------------> "archive" disk
                ^                         ^
                |                         |
           Unison on-                  BackupPC checks
           demand over                 for new files in
           SSH tunnel                  cache hourly

When a user initiates an on-demand backup via unison, the connection is 
over SSH (fewer potential firewall issues). After Unison finishes, a flag
is set on the cache disk to indicate to BackupPC that fresh files exist. 
BackupPC checks for this "freshness flag" instead of performing a ping of 
the client. If new/fresh files exist on the cache, then an rsync based 
backup is performed (of the host's directory of the cache disk) and the 
flag removed. (There's a lot more logic and checks to prevent simultaneous 
operations that I'm omitting here.)

This setup allows mobile users to backup and restore files from the most 
recent backup (the one on the cache disk) using the Unison gui. If an older 
version of a file is needed, the user can log into the BackupPC server's 
CGI and retrieve it from a prior backup.

This provides a near-optimal solution, I think, for laptop backups. The 
very first backup of a laptop may take a few minutes if there is a lot of 
data (so should occur on the local LAN if possible), but future backups for 
most users take under 5 minutes!

If anyone is interested in my exact setup (pre and post dump scripts, 
backuppc config, client backup script, etc) please let me know. If there's 
sufficient interest I'll clean them up a bit, removing the site-specific 
bits, and post them to the web.

Cheers, Stephen
--
Stephen Joyce
Systems Administrator                                            P A N I C
Physics & Astronomy Department                         Physics & Astronomy
University of North Carolina at Chapel Hill         Network Infrastructure
voice: (919) 962-7214                                        and Computing
fax: (919) 962-0480                               http://www.panic.unc.edu

  Don't look back. The lemmings are gaining on you.