I strongly suspect a flaw in your statistics: I'm willing to put money on this site having a spikey workload, not a constant workload. There are probably hours in a row that 6 of those servers sit idle.
Rant: I wish technical sites would stop using req/day as a metric. It leads to the op type of analysis. At the very least, such articles could use a format of "X req/day peaking at Y/s". Maybe if the NYT was writing it would be ok to use req/day but a sight who's tagline is:
"High Scalability Building bigger, faster, more reliable websites." should know better.
Sorry for that late reply, IMO, that title was fine, it did it's job well. My rant, etc, was about the stats section in the article itself. It still uses a flat time model, on the scale of N things/day instead of a more representative N things/day (X things/(smaller than day time unit) at peak).
Rant: I wish technical sites would stop using req/day as a metric. It leads to the op type of analysis. At the very least, such articles could use a format of "X req/day peaking at Y/s". Maybe if the NYT was writing it would be ok to use req/day but a sight who's tagline is: "High Scalability Building bigger, faster, more reliable websites." should know better.