You need to keep in mind that every volume you define to ADSM will be given
a separate thread, so creating 10 volumes on the same disk is definately
going to cause head contention.  10 threads fighting for the disk at the
same time would do a pretty good job of grinding your performance to a halt.
A more ideal situation is to have one volume per physical disk.  If you're
using a RAID set, it isn't as simple... :)

Paul