Tell me how you measure me and I will act accordingly.
25 years ago I visited Venezuela in South America. We entered the country through the Amazon coming from Manaus in Brazil. As we passed the border the dirt road changed into a paved road and the cars started to grow in size. After a while I asked our Landcruiser driver how the Venezuelans could afford driving such a big cars and he explained that the gasoline was cheaper than drinking water. At first I didn’t believe him but when he filled up his car at the petrol station he had to pay less than a dollar. Just check http://www.marketwatch.com/story/low-gas-prices-plague-venezuela-2011-03-16 and you can read that hardly anything has changed in Cháves country.
Why this story? Well, this is what came up to me when I heard an IT manager talking about energy usage in his data centre. He had no Idea how much energy his data centre consumed and no clue about PUE. Actually he was not interested in this information because it wouldn’t make his Data centre more reliable or perform better. Which both isn’t true as I will explain later. But first another short story.
My youngest daughter just became 14 last November and se got a new telephone. As parents you are uneasy if they bike home alone from school so that why she needed a new smartphone…. . With the new phone came a 250MB data limit. After a couple of days she asked me how she could get an idea of how much data she had used. I told her that she could wait until the end of the month when the phone bill would be mailed by Vodafone. And what if I use more than 250MB? That will cost you €2.50 per MB I said. So we ended up looking at internet where I found a great Android app “Traffic Monitor”. It not only measures the used Internet traffic, but it also tells you how much you use on Wi-Fi and even better it specifies exactly how much every individual running app uses. My daughter found out very quickly that the free downloaded game made contact to the internet every time she played it to download a large amount of data to show an advertisement. She was also very happy to find out that Whatsapp is “good” app with minimal data usage.
This is exactly what is happening in a data centre if you don’t measure where the energy is going you can’t manage it. PUE can be the same for the IT manager as gas mileage for the Venezuelan, if you don’t have to pay for energy you’re not interested in how much you use. And if you want to monitor your PUE because energy consumption is your concern then you need tools to measure it. And the way to do this correct is to measure all the users off energy and not only the IT and total facility part as is strictly enough to get a PUE figure. Only if you measure all energy using equipment in a DC individual you will get a feeling where the energy savings can be made. While measuring individual equipment we found out that a part of a fresh air system was short circuiting, bringing heated exhaust air straight back in to the air intake. The cooling system was kicking in the compressor resulting in high energy usage while the outside air was supposed to be cool enough to run on free cooling. A outside air deflector solved this issue and dramatically improved the PUE.
And don’t wait until the end of the month or even worse the end of the year to get your kWh and PUE report, but study, as with the phone app, your actual power usage under different circumstances to get a feeling for the performance of your DC.
And what about the IT managers reliability and Performance. Measuring energy to individual equipment gives you almost for free information on electrical currents nearing critical limits. Gives you information on voltage, power factor etc. helping you to prevent or detect critical situations resulting in lower failure rates and higher reliability. No the microprocessor won’t run faster when you measure the power consumed by the computer but if you know how much current is going through the rack PDU it is no risk to install extra cpu power if needed.
I only wonder why Venezuela is not yet crowded with Data centers… The beaches are nice and the people are friendly. Maybe something for a next challenge?