The appliance comes with vSphere Essentials Plus and above.
The VM's are duplicated on an individual basis. Meaning, one can do things like having the critical server replicated every four hours, but less critical ones every 24 hours.
VR can replicate either in the same datacenter or across a WAN. For my quick testing I replicated a VM from my lab cluster, to another physical ESXi server on the the same subnet but a different VMware Cluster. This meant I only needed one Virtualcenter Server and one vSphere Replication Appliance.
VR is an appliance so it installs much like any other appliance in no time at all. Configuring VR was just a matter of telling it what VirtualCenter server to talk to, where the source and destinations are.
Configuring a VM for replication is a simple right-click and six questions.
This is what the destination datastore looks like after a successful replication. The replicated VM does not show up in the machine inventory. When browsing the respective folder, one may notice there is not .vmx file so there is no option to add it to inventory and power on the VM. In order to use the replicated machine go to Home, vSphere Replication, "Replication Server", click the VR server, then the Monitor tab. Highlight the VM in question, and choose recover.
Here are the options presented during the restore process. One can also see status of the replication on this screen shot.
This scenario only works to recover the VM's to the recovery server, it will not restore the VMDK's back to the original server. One would have to copy off the VMDK to another storage to get the VMDK back to its original location. It could recover the VMDK back to its original location if both ESXi server had access to the same storage. In my lab, direct attached storage was in use.
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