High Availability

We might’ve heard this term in the past. Companies often migrate to the cloud to achieve high availability. In this lesson, we’ll cover what high availability is and how we implement high availability.

In simple terms, high availability is the ability of a system to operate continuously without any failure. Here are some key insights:

• In providing services to the end user, five-nines availability means the system or product is available 99.999% of the time.

• High availability is critical in situations where the systems should remain operational 24/7. People’s lives depend on these systems, for example, railway ticket booking, flight tickets, doctor’s appointments, and so on.

• Highly available systems architecture must be well-designed and thoroughly tested before they’re ready for release on production.

How to track high availability

• Single point of failure: It can be considered as a zone that can cause the whole system to fail if that zone fails. If an application runs on one server, that server is a single point of failure because if it fails, the application will become unavailable.

• Failure detection: Failures must be visible, and systems should have built-in automation to handle these failures. There should also be built-in mechanisms to handle common shortcomings.

Keynote: The more complex a system is, the more difficult it is to ensure high availability because the points of failure counter increases in a complex system.