Why does my incremental backup tar file (using Ubuntu sbackup) include mostly files that are unchanged?

Question

Ubuntu 10.10 sbackup, very handy, works fine. Backing up to external hard drive.

But I notice that the full backups are 50 GB or so and the incrementals are 450MB. Fine except that most of that 450MB are files that haven't changed.

Any idea why? Or how I can find out what command sbackup is doing to see why it's picking up these unchanged files?

Answer 1

Not only is the above true for me as well, but some of the incrementals are as large as the full backup. This makes no sense at all.

As nice as is the interface of sbackup, I think it's time to look for a different solution.