Many high-end systems that have heavy use and carry a lot of data have a failover system in place. This can be as simple as allocating additional resources by bringing more web servers online, to moving the entire operation to a back-up. Failover testing is used to verify the system’s ability to continue day-to-day operations while the processing part is transferred to a back-up. It can determine if a system is able to allocate additional resources when needed, or even if it’s able to recognize when the need has arisen.
One example of failover testing: You have four webservers under a heavy load and one of them crashes. Does the load balancer react in the correct manner? Can the other three web servers handle the load? Does the crashed web server restart itself or does it require manual intervention? Is there an automated notification system and did it notify the correct people at the right time?
By testing these things in advance, IT teams can have a benchmark for the future. They can rest easy with the knowledge that they can bring down a server for maintenance without significantly impacting production. Managers can have the confidence that in an extreme situation, the system’s redundancy is capable of handling the problem without downtime, thus keeping the company’s image intact.
Generally completed as part of a performance testing plan, failover testing is vital to verifying the readiness of a production system. QA Mentor’s Performance and Capacity Planning Services were designed to test failovers in addition to all other performance testing facets.