I love this stuff. Note the efficiencies:
- The hard drives (top), the most failure-prone components, are held in with Velcro for easy swaps.
- The power supply (left), also attached with Velcro, probably provides the only case ventilation with its exhaust fan, ensuring that air only flows where they want it to.
- The specially-made power supply only outputs 12V and ground (no 5V rails) to a specially-made motherboard that doesn’t need 5V rails.
- The servers each have a backup 12V battery (right), saving massive amounts of energy wasted by multiple conversions in traditional UPSes (120VAC in, stored as 12VDC, 120VAC out, converted to 12V/5VDC by PSU).
Since air conditioning is extremely power-hungry, efficient separation of hot and cold air is essential. It looks like they move all of the hot air to channels along the outside walls of the shipping container, leaving only the center air-conditioned. That way, cold air doesn’t need to run along the exterior walls in hot weather.
Those Google people are smart.