Backup doesn't complete

I have a ReadyNAS Ultra-6. It is working perfectly and is really serving me well. BUT: I've just recently tried setting it to backup [I got another NAS _just_ to serve as a backup target for the ReadyNAS]. The new NAS [a smallish Iomega] seems to work fine, also. So I went and configured a simple backup on the ReadyNAS of the one share with active data on it to write to the new NAS. It started at 1AM and it is now nine hours later and it hasn't finished yet -- still "in progress". there aren't timestamps in the log, but from what I can tell it finished writing all the files to the other NAS hours and hours ago. And if I look at the backup NAS, a cursory scan seems to indicate that, indeed, the files are all there [about 65 gigs worth of stuff]. But still it is running and doing something. The backup NAS is still showing activity, but I can't guess what it is, the logs on the ReadyNAS don't give any indication as to what's going on.

How long should a smallish backup take? And what has it been doing for the last 8-or-so hours after it finished actually copying all the files over to the backup NAS? Thanks!