Judging by a conversation I had on #appengine at irc.freenode.net, I'm clearly not the only person baffled by GAE pricing, so I figured I'd throw this up here and ask for clarity. Essentially: given an app with the figures below, what should its "CPU time" bill be per year?
Suppose: h = Google App Engine's charge per hour for CPU time. Currently, h = $0.10 f = Google App Engine's daily free quota of CPU hours. Currently, I think* f = 2853.5 t = total registered users s = simultaneous users. Assume = t * 0.2 e = (requests/second)/simultaneous user. Assume = 0.5 r = requests/sec = s * e R = requests/day = r * 3600 * 24 p = CPU hours/request. Assume 150ms/request. I.e. assume p = 0.15/3600 c = CPU hours/sec = r * p C = CPU hours/day = c * 3600 * 24 y = average number of days in a year = 365.25 B = CPU time bill per year = (C - f) * h * y Therefore, C = t * 0.2 * 0.5 * (0.15/3600) * 3600 * 24 So suppose I get 10000 registered users, that means C = 3600. In that case: B = (3600 - f) * h * y = 9146.5 * $0.10 * 365.25 = $40415 to the nearest dollar Is that right, or have I misunderstood what CPU time is, how it is priced, or how the quotas work? *The free daily quota[1] is not clearly expressed, but I think it's 6.5 hours for general use plus 2,487 hours for datastore manipulation: 2853.5 hours/day in total, assuming that my app mostly spends its time handling requests by using a controller to generate views on the models in the datastore, and allowing CRUD operations on those models. [1]http://code.google.com/appengine/docs/quotas.html -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en.
