Availability Sets on Windows Azure
If you wonder why we care about availability sets you better read here
One VM == availability not guaranteed
We will need to setup availability sets and redundant Virtual Machines (VMs) and services for apparent reasons. We are going to implement an Availability set where problems on the datacenter where you host your application or scheduled maintenance tasks may not bring down your precious service.
According to Microsoft and by reading closely their Windows Azure SLA (until today) we see that Microsoft ensures a 99.95% availability if and only if you have availability sets deployed.
The way to setup availability sets and whatever is contained in them, depends heavily on the nature of your application.