Friday, April 10, 2009

Kill the LEDs

LEDs are much more efficient than traditional bulbs and can be better than the new energy efficient ones as well.

But there are certain LEDs out there that are just a complete and utter waste of time, I'm talking about those that are INSIDE computers. No idea if there are any inside the MacBook Pro I'm using now but I know there are a bunch inside my home PC. I'm not complaining about external LEDs that are meant to actually convey something just those that are either excessive or inside something. Over in the data centre there are even more, lots and lots of LEDs that flash away all day long in rack-mounted kit that no-one will look at unless there is a problem.

But I hear you cry and LED uses very little power lets say its a 10mA at 5v, it is a pitifully small amount of power, 50mW and half the time they are off before they flash on again so the average usage is only 25mW/hr.

Nothing at all. But then there aren't just one are there? There are ruddy loads. Lets take a switching rack, just one. 4 sets of 10 boards all slipped in with about 4 external LEDs per board. Internally however there are around 20 LEDs on the board, these are LEDs that are NEVER seen outside of a test lab and there you don't rely on the LEDs you start using some proper kit.

So 20 x 4 x 10 x 25 = 20,000 mW/hr or 20W/hr.

Suddenly its looking quite a bit more interesting, across the data centre we are now talking about potentially kilowatts an hour of electricity powering all of these LEDs that no-one cares about. Even the ones on the outside should be added to this list. Why are they flashing all the time? Why not just have them activated when someone needs to test them, a remote (or even local) switch that allows them to start flickering away if required. In a lights out DC environment it really is pointless to have these flashing lights all the time.

Now I don't know many LEDs go into normal blade or rack-mounted kits these days but they do seem to have quite a few LEDs that could disappear. I've made the comment before that these flashing lights symbolise everything that stands in the way of the progress of cloud computing.

So like the environmentalists who got hotels to stop washing everything every day by showing them it could save them money I say that people who support cloud should object to these flashing lights on environmental grounds.

LEDs in data centres are a small part of the power consumption in a data centre but that doesn't mean we shouldn't make that small step. So lets start the campaign by asking hardware suppliers "how many internal LEDs does that product have" and asking what the power consumption of those LEDs actually is.

They aren't needed so lets turn off the flashing lights.

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