Our software doesn't do just a simple copy, which would be much quicker. It has to do encryption, compression, digital signing, and a LOT of other things. Here is an article describing the process:

http://help.remote-backup.com/index.php?/Knowledgebase/Article/View/389/0/why-does-it-take-so-long-to-do-a-backup

Of course some of the above doesn't apply to the first backup to USB drive using the Copy-To-Disk function, but it DOES introduce other bottlenecks, like the speed of the USB drive and especially the speed of the USB port. USB port speeds can be incredibly slow sometimes.

"Normal" speeds for copy to disk can from 2 GB per hour to 7 GB per hour depending on how much data you selected to back up and what kind of data it is, the USB port speed, USB drive speed, CPU speed and loading from other applications, available RAM, and even upstream bandwidth.

The Copy to Disk function DOES contact the RBS Server to hash space for the backup, for when it is imported to the Server, (but it does not send backups to the server) so a really slow upstream internet connection has an effect on Copy-to-Disk.

You can attempt to speed up the process by increasing the CPU Utilization from normal to high, allocating more RAM, using a faster USB port, and perhaps other factors.

It is not at all unusual for a large data set to take several days to complete a Copy-to-Disk.