High Availability


 A failover feature to ensure availability during device or component interruptions.

 Source: NIST NIST SP 800-113

An approach or design that minimizes or hides the effects of configuration item failure on the users of an IT service. High availability solutions are designed to achieve an agreed level of availability and make use of techniques such as fault tolerance, resilience and fast recovery to reduce the number of incidents, and the impact of incidents.

 Source: ITIL

High Availability (HA) is a system or service design that ensures the availability of a system or service for a certain period of time. It is typically used to describe systems that are available and reliable with minimal downtime. HA systems are designed to have redundancy built in so that if one component fails, another can take over without affecting service availability.