[K12OSN] Data Storage - Redundancy and Backup Suggestions

[Les Mikesell]

Rob Owens wrote:
> A backuppc question:
> 
> If I'm using rsync as the backup method within backuppc, is there any
> need to do a periodic full backup, or are incremental backups enough?
> 

With the rsync method, even full backups don't actually transfer file 
files again and you should do them periodically.  Before the 3.x 
versions, backups were always based on the last full, so the 
incrementals would transfer an increasingly large set of files. Now it 
is possible to base them on the last incremental instead, but it is 
still a good idea to do the fulls.  The difference is that an 
incremental skips files where the name, length, and timestamp match your 
existing backup.  On fulls, both copies are read and compared with the 
rsync block checkup algorithm.  This takes some CPU time at both ends 
but not much bandwidth and verifies that your current copy is still 
good.  Also during full runs the backup directory is completely rebuilt 
for faster access on the next run.

-- 
   Les Mikesell
    lesmikesell at gmail.com