What is the minimum disk drive configuration which will function on a Excite system with HP Linux Workstation?

What is the minimum disk drive configuration which will function on a Excite system with HP Linux Workstation? see long description The system is an Excite running 11.0 M4 software, this site also has an Excite3 system running 12.0 software. This is a research site. They have had a few issues in the past where MGD reset would fail and looked like a hardware issue, but turned out to be software related and software reload corrected. The FE is trying to position himself to be able to determine better if issues like this are hardware or software for the future. What he wants to do is get some extra drives for this site and load them up with software in order to have a set of test drives on the site with known good software which they can install to determine if the issue is hardware or software related. His ultimate question is, what is the minimum drive configuration which you can have in the HP workstation and have functional software for this test setup? He would like not to have to order all 3 drives for this. He is hoping that he could load the software on the system disk drive only and keep functionality for this test.