Obviously, production may have many more than two so it can handle the intended load, but this staging environment need only have enough servers to adequately test the failure and recovery scenarios.
In the event of a failure, you simply quiesce the test workload and let the DB2 standby assume the load of the failed server without consideration for throughput reduction.
DPF failure diagnosis is carried out by on-board smoke hanging test, to verify the feasibility of this diagnosis strategy, no-load, medium load and full-load test are respectively carried out.