Following up on my previous post regarding PUE. What does it mean for an organization to have a low or high PUE?
PUE = (Total data center facility + IT equipment power utilization / Total IT equipment power utilization)
where PUE is a ratio, e.g. a PUE of 1.5 means that for every 1kW of IT equipment (be it server, network devices, firewalls, etc.), it would require 0.5kW of power to keep the data center operating to maintain sufficient cooling, de-humidification / humidification, availability (UPS), etc. to sustain and house the said IT equipment.
Hence, for an organization with, say 100 racks of IT equipment, and average of 6kW of IT equipment per rack, the total IT equipment power utilization would be approximately 600kW in total. If their PUE is 1.9, that means it would require 600kW x 1.9 = 1,140kW to keep the entire data center up and running. Supposing this organization is situated in a country and location with electricity tariff of US$0.10 per kW/hr. It would cost this organization 1,140kW x 24 hours a day x 365 days a year x US$0.10 = US$998k p.a. to operate its data center (assuming the IT equipment payload are constant and doesn’t change in that year).
If you could significantly reduce the PUE to 1.5 instead of 1.9. What this means is that this organization would now only need 600kW x 1.5 = 900kW to keep its data center up and running. Computing the operating costs for utility = 900kW x 24 x 365 x US$0.10 = US$788k p.a.
A reduction in PUE, from 1.9 to 1.5, for a data center with IT payload of 600kW, will yield an approximate reduction in utility operating costs by US$210k p.a.
So, the significance of PUE to a business is basically a measurement of how efficient is the organization operating its data center facility. Finding ways to reduce PUE is to find ways to reduce its operating costs.
Tags: Efficiency, Metric, OPEX, PUE