Gmail shows Office 365 how to meet a 99.9%+ SLA

The really bad thing about the Office 365 outages in August and September is that the accumulated 330 minutes of downtime means that Microsoft cannot meet its published Service Level Agreement (SLA) of 99.9%. To their credit, Microsoft has already acknowledged that they failed to meet their SLA in August and September and compensated affected Office 365 users with a 25% credit. However, losing 330 minutes means that it is impossible for Microsoft to meet its SLA performance for the whole of 2011.

According to the SLA Calculator, the downtime permitted by a 99.9% SLA is 8h 45m annually, or 525 minutes. Office 365’s downtime is 330 minutes but that’s for just the three months since its formal launch on June 28. Thus, we can conclude that Microsoft will be unable to meet a six-month SLA of 262.5 minutes (525/2). Of course, others might well have a different interpretation and that’s the joy of figuring out just what the data really means, hence the famous remark about lies, damned lies, and statistics!

The point is that Microsoft has some work to do to restore customer confidence around the ability of Office 365 to meet its SLA (and better) over a sustained period. Meantime, over in Mountain View, Google is probably chortling into their cappuccinos because Gmail has posted sparkling numbers for 2010 and the first six months of 2011. My take on the situation is now available on

Have fun!

– Tony


About Tony Redmond

Lead author for the Office 365 for IT Pros eBook and writer about all aspects of the Office 365 ecosystem.
This entry was posted in Cloud, Email, Office 365 and tagged , , , , . Bookmark the permalink.

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