Failover is a critical concept in the realm of IT infrastructure, particularly concerning availability and reliability. It refers to the automatic and seamless switching to a redundant or standby system, server, hardware component, or network when the primary system fails or experiences abnormal termination. This process ensures that services remain uninterrupted and minimizes the negative impact on users.
Key Aspects of Failover
Automatic Switching: Failover is designed to occur automatically without human intervention. This is a key distinction from switchover, which requires manual intervention[1][2].
Redundancy and Standby Systems: Failover relies on having redundant or standby systems that are ready to take over immediately when the primary system fails. These systems must be kept in a state of readiness to ensure a smooth transition[1][5].
Heartbeat Mechanism: Many failover systems use a "heartbeat" mechanism, where a secondary server monitors the primary server through regular signals. If these signals stop, the secondary server takes over the operations of the primary server[2][5].
Failover Clusters: A failover cluster is a group of servers that work together to provide high availability and fault tolerance. If one server in the cluster fails, another server in the cluster takes over its workload, ensuring continuous service[1][2].
Virtualization: Failover can also be implemented using virtualization, where virtual machines (VMs) are used to simulate physical hardware. This allows for failover processes to be less dependent on physical hardware and more flexible[2][5].
Failback: This is the process of returning operations to the original primary system after it has been restored to working condition. Failback ensures that the system can revert to its normal state after the issue causing the failove...
