Burned By Gmail Outage? Google Will (Almost) Buy You a Postage Stamp.  Apparently the SLA for Google Apps will get you 3 days if uptime dips below 99.9% for the month.  At $50 annually for the service, that’s $0.41.  (Google has decided to pay out 15 days credit, anyway.)

Service credits from the SLA:

Monthly Uptime Percentage	Days of Service added to the end of the Service term, at no charge to Customer
< 99.9% – ≥ 99.0%	3
< 99.0% – ≥ 95.0%	7
< 95.0%	15

That’s $0.41, $0.96, and $1.91 credit for over 43.2 minutes, 7.2 hours, and 36 hours of downtime, respectively.  I realize that across an entire business, that could potentially be a thousand credits or more, but what business would see a $1.91 per user credit as adequate for 36 hours of downtime in a month?

From these two register articles, Google’s email service goes down and Google blames Gmail outage on data centre collapse, it looks like the downtime was about 2 hours and 15 minutes, but there are some reports of outages as long as 4 hours.

There is a nice article on High Availability on Wikipedia to compare uptimes on a weekly, monthly, and yearly basis.