Lets just get straight to the point, Azure SQL Database across all service tiers gives you the customer a SLA of 99.99% up-time. This means potential unavailability periods shown below.
Good, bad, you decide. The point is that even in the cloud we “could” potentially encounter downtime. Can you improve on 99.99%? Well that was the question I asked Microsoft, I was given a “wishy-washy” answer that yes you can by using failover groups ( I’m guessing the read/write endpoint is key here ) to improve the up time. I then pressed on what sort of figure in terms of nines does this provide, to no avail.
So what happens if up time is less than 99.99% or even worse 99% (ouch). Service credits are available as shown below.
Arun also includes some of the exceptions Microsoft has. Most of these are “you messed up” types of exceptions, but not all of them.