All of the data centers I've worked with have had technicians onsite 24/7. There's just a lot of stuff that sometimes needs doing that's easier with someone there.

I'm sure they pull in from outside the area for large jobs like major equipment refreshes or major network changes. But for day to day stuff (and there's always day to day stuff), it's just a couple people. Some days, they're very busy and my lowpri tickets take a long time to get worked, other days my tickets get completed in minutes.