1.Expensive hardware-hundreds of thousand of server.
2.Massive density of power.
3.Downtime affects all dependent businesses
+ Redundancy on all levels is essential.
4.Power,pipe (cooling),ping (connectivity) limitations.
5.Temperature: Sensors will measure the heat being generated by equipment as well as the air-conditioning system's intake and discharge.
6.Humidity and moisture: Sensors ensure high moisture levels won't corrode electronic elements and low levels won't cause static electricity.They alo monitor for leaks in cooling equipment,pipes etc
7.Airflow: Sensors ensure air is properly flowing through racks and to/from the air-conditioning system.
8.Voltage
9.Power
10.Smoke
11.video surveillance