I have been tasked with computing the cooling requirements for new server rooms and have been trying to use the Datacenter Capacity Planner tool to accomplish this.
I am confused by the results for Power (wattage and cooling). I am configuring racks of 1750's, 1850's, 2650's, 2850's, and 2950's. The wattage and cooling numbers come back the same if I configure them with redundant or non-redundant power supplies. I don't see how that can be accurate.
For example: a PE2650 shows thermal watts usage of 357W and a need of 0.1 tons sensible cooling whether it is configured as a single or dual power supply unit. Is that for one or two power supplies? Also, is it possible to get the plain BTU generation instead of the sensible cooling suggestion?
What you'll find is that this tool was created way after some of the products you mention. The second number in each name (the "9" in 2950) is it's generation number, the 9 being the 9th generation. With this later hardware, there is accompanying power supply efficiency information associated with it. The logic would suggest that with a redundant configuration, the load is being shared between 2 supplies, they are loaded half as much, and are operating at an efficiency that is lower due to the lower utilization. The older servers do not carry the efficiency variation within their data attributes. There is a single number efficiency associated with them, so whether they are heavy loaded (non-redudant) or light loaded, the tool thinks they are the same efficiency. Sorry, but we just lacked the data at the time the tool was built.
To get BTUs, you can change to metric by clicking the "properties" button. It's going to also change to degC, kg, and cu.m/hr
Kong Yang
180 Posts
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Posted January 13th, 2010 11:00
I have forwarded your concerns to the data center infrastructure team for clarification. A response is forthcoming.
KongY