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Comment by tdrdt | Hacker News Reader

"For most purposes, electricity is almost a rounding error in datacenter asset management concerns."

I don't think this is true. It is not only power consumption but also power backup. If you can use smaller diesel engines and smaller battery packs this will lower the cost.

And why do you think datacenters have been raising temperatures? It saves a ton of money: https://www.datacenterknowledge.com/archives/2008/10/14/goog... HP estimated they saved 8 million. That is not a rounding error.

A server that uses less power will also generate less heat.

I have to admit it is years ago I worked for a company owning datacenters but at that time the highest costs were always: power and connectivity.

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That article cites a 100,000 sq. ft. data-center as the source for that $8 million savings estimate, along with roughly a 30% power savings figure. No mention on the period, so presumably it would be a TCO for the servers going into the initial buildout.

100,000 sq. ft. is roughly enough space for about 250,000 1U servers. Say conservatively the servers are in the ballpark of $2,000 each. That's $500 million just in server hardware costs. If the total electric cost is around 3*$8 = ~$24 million over their lifetime, then we're talking about <5% of just the server expenses. Never mind the facility and staff costs (and, as you've said, connectivity).

So maybe not a rounding error, but way down the priorities list.

These are AC costs not total costs and the $8m is probably an annual figure - although it's not clear.

Yeah, unfortunately it's a bit vague on the period. It is not unreasonable to assume an annual figure, in which case you're looking at something closer to 20% of the server costs for A/C power (assuming an average life of about 4 years).

Problem is, that sounds high... the coefficient of performance for chillers is around 4 to 7 [1]. That puts ~15-30% of the total energy demand from chillers, though often datacenters do budget a factor up to about 60% of equipment power demand for cooling power demand. Sum energy related expenses for datacenters tends to be around 10-15% of the total costs [2]. So it would be odd to have such high cooling costs. A TCO over 4 years seems more in line with typical figures.

  1: https://www.energy.gov.au/sites/default/files/hvac-factsheet-chiller-efficiency.pdf
  2: https://www.missioncriticalmagazine.com/ext/resources/MC/Home/Files/PDFs/(TUI3011B)SimpleModelDetermingTrueTCO.pdf

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