Little boxes around the edge of the data centre?

spaceyhackerlady writes: We're looking at some new development, and a big question mark is the little boxes around the edge of the data centre — the NTP servers, the monitoring boxes, the stuff that supports and interfaces with the Big Iron that does the real work.

The last time I visited a hosting farm I saw shelves of Mac Minis, but that was 5 years ago. What do people like now for their little support boxes?