[mdlug] Periodic backup software (dis)recommendations

[John Wiersba]

I would recommend backing up to an external disk or server, not using CD or 
DVDs.  There are many reasons to do so, one of which is the convenience of 
accessing your backup for restoring files or just exploring previous backup 
points.

Up until recently, I used a variation of rsync called rsnapshot (a perl script 
which calls rsync).  It keeps snapshots of your backed up data using hard links, 
so that unchanged files do not take up any extra disk space in subsequent 
snapshots.  


Now, I just use rsync directly with a little shell wrapper, for greater control 
over my specific requirements.  On modern systems rsync can handle the hard 
linking itself -- you just need to determine the directory to hard link to 
(namely, your most recent snapshot directory):

   /usr/bin/rsync -a    \
      --numeric-ids     \
      --relative        \
      --delete          \
      --delete-excluded \
      --link-dest=$PREV \
      $EXCLUDES         \
      $FROM             \
      $TO

You can add -x and -H if appropriate.  PREV is the previous snapshot directory, 
EXCLUDES is a list of exclude options (optional).  FROM is the source 
directory.  TO is the new snapshot location.