"The Simple Storage Service (S3) provided by Amazon comes with a Service Level Agreement: If the Monthly Uptime Percentage is between 99% and 99.9%, you get a 10% refund; if the Monthly Uptime Percentage is below 99%, you get a 25% refund. The Monthly Uptime Percentage is computed in a fairly straightforward manner: Divide the month into 5-minute intervals and compute the Error Rate (failed requests divided by total requests, treating 0/0 as 0) for each interval; compute the average Error Rate over all the 5-minute intervals in the month; and subtract this value from 100%.
If the probability of a request failing during the n th 5-minute interval is p(n), and the number of requests issued during the n th interval is determined solely by p(n), the expected value of the Monthly Uptime Percentage is 100% minus the average value of p(n) over all the intervals; put another way, you can't cheat by waiting for a high p(n) and then quickly running up the failure count by issuing lots and lots of requests. " --clip-- More at http://www.daemonology.net/blog/2008-10-23-hacking-the-amazon-s3-sla.html Juha-Matti _______________________________________________ Fun and Misc security discussion for OT posts. https://linuxbox.org/cgi-bin/mailman/listinfo/funsec Note: funsec is a public and open mailing list.
