As with backups, you should test from time to time to see whether your replicated VMs are actually working in case you need them in a disaster.
By using test failover, you will create a temporary VM on the replica server. You can play with this VM, do some tests and more without interrupting the replication between the production VM and the replica VM.
There are more possibilities (use cases) where you can use this failover type. Let’s say you have a certain application (e.g., an email service) that you would like to upgrade. And for the sake of simplicity, let’s say that the email service exists out of a domain controller (needed for authentication, service accounts, etc.) and the actual email server.
On the replication side, you can create the test failover VMs, put them in a quarantined network (in order not to interfere with the running production servers, as explained in the section on network configuration on the replica) and then use those two test failover VMs to perform some upgrade tests.
This situation is ideal for performing tests on a real-life environment (after all, the VMs are replicas of your production environment) and it’s perfect for building a change management plan.
In Figure 26 you can see how to build such a setup.
The procedure of doing a test failover is very simple, but it requires a final step that can’t be forgotten after all the testing!
On the replica server, right-click on the replica VM and select Replication… - Test Failover...(see Figure 27):
If you are using multiple recovery points, select the recovery point that you want to use and press Test Failover (shown in Figure 28):
In your list of VMs, you now see a VM with the same name and “– Test” as addition (see Figure 29). Note that you will need to start the VM manually.
After all of your testing and other tasks with those test VMs, you need to clean up. Right-click on the replica VM and select Replication – Stop Test Failover to stop the test, and this will clean up everything (see Figure 30).
A last note: When you are using extended replication, you can do the test failover on the extended replica without hurting the chain. This will provide additional possibilities in testing your environment.