Can you explain what is meant by Availability in systems?

Availability in systems is a characteristic that reflects the system's ability to be accessible and operational at the required time. In simple terms, it is the probability that the system will operate without failures and will be ready to serve user requests.

High availability is achieved through component redundancy, fault tolerance, monitoring, and quick recovery after failures. For example, if an application server crashes, a high availability system will quickly switch to a backup server, minimizing downtime.