First, let me define SLA as it relates to this discussion. SLA is service level agreement and for the facility minded individual is how we guarantee conditions at the server. We guarantee uptime and with properly corded devices we guarantee customers will not lose power. We also have temperature and humidity SLAs. They might be do not exceed 60-89 degrees f and 20-80% relative humidity for more than 4 hrs, for example. Now we have a target band tighter than that but that is our promise.
With that understood, we can start the discussion. Let’s say we have 2 MW busses with 4 primary and 1 redundant bus using static transfer switches to transfer to the reserve (redundant) bus. Let’s say that each bus has 1400 kW of UPS power, requires 100 kW for house loads, 100 kW for UPS losses, 40 KW for lighting, and 760 kW reserved for…
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