We created clear plastic covers to cover empty spots on the server rack to make sure no cold air travels without going through servers. We found this to be very effective way to utilize as close to 100% of cool air.
錦糸町の天使 
コーチ探せる 
ロッキーおしょう 
bokushi 
ウチクラ ケンイチ 
PSPCF 
カワシマヒロキ（ひーさん） 
Junya Suzuki 
Seattle Execs. 
木曽町田中屋豆腐 
SanDiegoTown & LosAngelesTown