It has been over a month of troubleshooting but I finally figured out why my DroboPro was locking up my system, forcing a reboot of both my computer and the device, when connected via iSCSI. I narrowed it down to the daspi kernel extension that I installed with MakeMKV (http://www.makemkv.com).
Basically after light to moderate usage on the Drobo, any program that was accessing it would become unresponsive, and any new process (like double clicking on it in the finder) would also lock up. Killing the process and relaunching would sometimes help that process, but nothing could access Drobo again until reboot of both devices.
Took a long time to narrow down the cause. Existing OS had the problem, clean install didn’t. Started with a fresh install and slowly added software until I started having the problem after a Parallels and MakeMKV install, but not before. Removed daspi and haven’t had a problem since. Only seems to happen with version 2.0 of the Drobo Dashboard (iSCSI initiator) and newer, FYI, but Lion requires at least 2.0.[hr]
Well, I guess never mind for now. Every other time (20+ times) it has happened within 5-10 minutes. This time is was a few hours, thought I was out of the woods. Well, I will let you know what I find.