Even though the SLA for every solution might differ, the guaranteed availability is 99.9% or more. It is also possible to restore have up to 99.95% availability, with the use of some backup options.
The Azure cloud environment operates on a high number of servers, and in case one server failed, it is automatically separated from the cloud system.
While an on-premises system concentrates on “having a server which doesn’t fail”, and which is impossible, the Azure cloud simply filters out the machine that failed, and looks for the server.
Thanks to this, Azure is always prepared for hardware issues in the server park and has several scenarios prepared to protect your system.