Release It!, 2nd Edition

The Scope of the Challenge

In the easy, laid-back days of client/server systems, a system’s user base would be measured in the tens or hundreds, with a few dozen concurrent users at most. Today we routinely see active user counts larger than the population of entire continents. And I’m not just talking about Antarctica and Australia here! We’ve seen our first billion-user social network, and it won’t be the last.

Uptime demands have increased too. Whereas the famous “five nines” (99.999 percent) uptime was once the province of the mainframe and its caretakers, even garden-variety commerce sites are now expected to be available 24 by 7 by 365. (That phrase has always bothered me. As an engineer, I expect it to either be “24 by 365” or be “24 ...