Lipstick on a pig: Facebook’s data center refit.


Vern Burke, SwiftWater Telecom
Biddeford, ME

I’ve just been reading an article today about Facebook retrofitting a data center and all the great energy efficiency gains. Unfortunately, sometimes the best retrofit method for a data center is dynamite.

Most of the modifications mentioned have to do with airflow. Now, I’ll be the first one to cheer for improving and controlling airflow for improving data center efficiency. The problem is, how BAD does your airflow situation have to be to have to run the cold air temperature at 51 degrees F?! I though data centers running in the 60s were out of date, 51 is just pathetic. It’s obvious that there was certainly room for improvement here, but the improvement effort only got them to 67 and that’s still lousy.

The big problem here comes from continued reliance on the obsolete raised floor as a plenum design. There are certainly far more reasons not to use raised flooring in a data center, including unproductive floor loading, expense, fire detection and suppression requirements, under floor housekeeping, metal whisker contamination, and a whole host of airflow issues. Since the Facebook retrofit is all about the airflow, I’m going to just address the raised floor airflow issues.

If you’re really serious about balancing your data center airflow, using a raised floor as a plenum is the last thing to do. First, under floor obstructions make smooth airflow next to impossible, even if you’re totally conscientious about housekeeping. Second, there’s zip for fine control of where the air is going. Need to add just a small amount of air here? Sorry, you take multiples of full tiles or nothing. Third, pull a tile to work on underfloor facilities and you immediately unbalance the entire system. Pull a dozen tiles to put in a cable run and you now have complete chaos across the whole floor. Finally, make any changes to your equipment and you have to rebalance the whole thing.

These things are so inefficient that it isn’t any wonder that a lousy design would need ridiculously cold air to make it work. 67 is certainly an improvement, now they’ve gotten things up to being only 5-10 years out of date.

When Facebook actually retrofits a data center all the way up to modern standards, I’ll be impressed. This operation is still a pig underneath, no matter how much lipstick you put on it.

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