Any Google App could be unavailable for more than 21 hours on a given day, and the company could still claim they had 100% uptime. That’s the gist of an analysis penned by Pingdom, who took a closer look at the Service Level Agreement for Google Apps.
The most interesting tidbit in the SLA, which applies for Gmail, Google Docs, Google Calendar and more (emphasis ours):
“Downtime Period” means, for a domain, a period of ten consecutive minutes of Downtime. Intermittent Downtime for a period of less than ten minutes will not be counted towards any Downtime Periods.
“Monthly Uptime Percentage” means total number of minutes in a calendar month minus the number of minutes of Downtime suffered from all Downtime Periods in a calendar month, divided by the total number of minutes in a calendar month.
True enough, this exempts Google from admitting it had up to 21 hours of downtime in one day (worst-case of course, see Pingdom’s calculation for more information about that as well a more likely scenario), because it ignores all unavailability under 10 minutes, which by today’s standards is a very long period even for free services (SLA applies only to paying customers, but still).
Google’s Apps SLA may guarantee 99,9% uptime, but this little loophole makes it darn easy for the company to honor that.