Q:

how to throttle file copy

I need to duplicate a 3TB disk by copying from one to another. They're housed in separate docks (no fan). It will take at least 8hrs to copy this much data through USB 2.0 and im concerned about disks overheating. 
Is there any utils to throttle the rate of files or MB/second copied?

A:

Software called UltraCopier allows you to limit the speed of the copy.

