In Hyper-V, VM replication is a disaster recovery feature. It creates a replica of a VM on a remote Hyper-V Server and then keeps the replica up to date. The VM on the remote host is not active, but can be made active should the VM's host for some reason fail.
With Hyper-V replication, the source VM host bundles up any changes in a running VM's VHD file(s) and sends them to the replica server on a regular basis. The replica server then applies those changes to the dormant replica.
Once you have a replica established, you can test the replica to ensure it can start should you need that. Also, you can failover to the replica—bringing the replicated VM up based on the most recently replicated data. If the source VM host becomes inoperable before it can replicate changes on the source VM, there is a risk of those changes being lost.
In this...