Hi.
I would strongly discourage you from connecting USB disks to your Core or Core/Hybrid, as USB disks consume CPU time in order to function, and the combination of running UpdateMedia (which is accessing the MySQL database) and running your USB disk(s) on the same machine, will undoubtedly raise your iowait percentage to raise to the point where the CPU is WAITING on the USB disks to finish their I/O, which blocks other I/O related processes.
This can manifest itself in many ways, such as the orbiter crashing when updating the Orbiters in a room when watching TV (because of the database accesses required to populate the TV guide), to slow media list viewing, etc. But basically, it is a _VERY_ bad idea to attach USB disks to a Core or Core/Hybrid.
It _IS_ OK to connect them to media directors and other workstations, however.
-Thom