I've been in Crete for the last few days and just over the hillside from the hotel I am staying at lies a large wind farm, generating electricity so hotel guests can leave their air conditioner on all day while they are beach side for the luxury of returning to a cool room. Most of the Greek hotels I have stayed at receive poor marks for power management. Rumor has it that so too does the #5 ranked Itanium supercomputer at CEA, the French energy agency. At 42.9 TFlops it has been estimated to use over 2 MW of power. A luxury not many organizations other than a national energy agency can afford. By contrast, the Tokyo Tech computer room, housing the 38.18 TF TSUBAME supercomputer uses only about 1.3 MW, including the power usage of campus administrative systems housed in the same center.
TSUBAME itself uses less than 1 MW. Fittingly, the Japanese Tsubame swallow, symbolic bird of the Tokyo Tech crest also is very energy efficient even when flying at full speed.
I expect power usage is one reason that Itanium systems on the Top500 list dropped from 46 to 36 entries while Opteron powered systems rose from 55 to 81. Speaking of power, here is another great shot from the basement of Tokyo Tech's computer room.
These batteries don't actually power TSUBAME's Sun Fire x64 compute nodes, they provide battery backup for TSUBAME's 1 PB of Sun Fire x64 storage servers running the Lustre parallel file system from Cluster File Systems. The energy efficient Sun Fire x64 storage servers can run for over 15 minutes on these batteries, allowing for safe shutdown of all file systems.
That is a wrap for today and tomorrow I'm off to yet another city, so you will probably have to wait until Sunday or Monday for my next TSUBAME installment.