Backup to Disk

Hi There!

Unfortunately due to issues with a ML350 G6 dismounting
volumes when I try and access any backup software, we are
forced to consider backups to disk.

I have organized a 1TB Array to be put into this G6 but now
I need a way to copy data from 3 volumes overnight and
unattended to the new array. Could someone suggest a nice
simple easy method ?