One thing NOT to do with your Xserve and terabyte Xserve RAID: DON'T lock the front security latch (little hex key hole). Because if you do this while the machine is booted, and the Xserve has a kernel panic and reboots itself, on bootup it won't see any of its peripherals, including the RAID. I spent a heartaching three hours today and several tense and expensive conversations with Apple tech support before I figured this out. (Apple didn't tell me the problem. I eventually found it myself in the manual when trying to figure out why I couldn't boot from a CD. Yup, that won't work with the latch locked either. Nor can you use a mouse and keyboard.)
Right now I can't figure out what that latch is good for, because you sure as hell don't want to use it on a production server.