What is the primary reason an organization might choose a parallel processing testing scenario over a fail over testing scenario?

Parallel processing allows for systems to be tested without taking them offline. This means that in the event of an issue with the backup systems or facility, the primary facility can continue to operate. Parallel processing does allow for more throughput, but organizations should not rely on this as parallel processing environments need to be able to handle the full load for the organization if the primary or backup fails. Fail over does test redundant systems and does not require organizations to create a significant issue. Instead, manual fail over processes are used to conduct fail over tests.