5-4-3 Failover and Failback Explained
Key Concepts
- Failover
- Failback
- High Availability
- Disaster Recovery
- Redundancy
Failover
Failover is the process of switching operations from a primary system or component to a secondary one when the primary fails. This ensures continuous service availability and minimizes downtime. Failover can be automatic or manual, depending on the system's configuration.
Failback
Failback is the process of restoring operations from the secondary system or component back to the primary one after the primary has been repaired or restored. This step is crucial for maintaining optimal performance and resource utilization.
High Availability
High Availability (HA) is a system design approach that ensures a prearranged level of operational performance, usually uptime, for a higher than normal period. HA systems are designed to minimize downtime by incorporating redundancy and failover mechanisms.
Disaster Recovery
Disaster Recovery (DR) is a set of policies, tools, and procedures to enable the recovery or continuation of vital technology infrastructure and systems following a natural or human-induced disaster. DR often includes failover and failback procedures to ensure business continuity.
Redundancy
Redundancy involves duplicating critical components or functions of a system to increase reliability, usually in the form of a backup or fail-safe, or to improve actual system performance. Redundancy is a key component of both failover and failback strategies.
Examples and Analogies
Think of failover as having a spare tire in your car. If you get a flat, you switch to the spare to keep driving. Failback is like fixing the flat and switching back to the original tire once it's repaired.
High Availability is akin to a well-stocked pantry. Even if you run out of one ingredient, you have backups to ensure you can still cook your meal. Disaster Recovery is like having a fire escape plan for your home. It ensures you can quickly and safely exit in case of an emergency.
Redundancy is like having multiple exits in a building. If one is blocked, you can use another to ensure you can still leave safely.