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VMware vSphere Replication has come a long way from its debut in vSphere 5. The major difference between vSphere Replication and Site Recovery Manager is that the former enables the replication of virtual machines at the virtual layer instead of at the storage layer.
Deploying and configuring vSphere Replication is fast and easy, once you know which architecture you need to deploy. Once you have finished installing vSphere Replication and have selected all the settings you need in the configuration process, you're ready to get to work.
Let's put VMware vSphere Replication to use by actually replicating a VM. Right-click the VM you want to replicate and choose All vSphere Replication actions > Configure Replication.
This will start a new wizard. If there was a remote site with a second vCenter Server, you would install another vSphere Replication appliance there and pair both sites together. If you want to add a remote site, click on the Add Remote Site button in the bottom right. Once you hit Next, you'll receive a prompt asking for the target site.
When the vSphere Replication appliance is first deployed, the vSphere Replication server is also deployed. That's why we can select vSphere Replication server in the third step of the process.
While choosing the target location, you must provide the host and data store where you want to store the replicas. I picked up an ESXi host and local attached storage, so, in this example, we'll replicate from VMware vSAN to another host outside vSAN cluster, which has some local storage.
The next step is to select the replication options. You can choose to enable quiescing, which could take several minutes and might affect the Recovery Point Objective (RPO) time. The other option is whether or not to enable network compression for vSphere Replication data. This reduces the network bandwidth that vSphere Replication uses on the source site, WAN and the target site. In this example, we're only using local hosts, so I left them both unchecked.
In the sixth step, configure the recovery settings for the VM. On this page, select the RPO time. A lower RPO time reduces potential data loss but uses more system resources as well as bandwidth. You also need to select the number of instances per day and the amount of days.
Once you hit finish, the replication of the VM is set and you can start monitoring the progress. The initial full replication might take some time depending where you replicate to and from, and how much bandwidth you have.
You can connect to see the progress. In vCenter Server, underneath the Monitor tab, choose vSphere Replication and then click Outgoing Replications. You will see all the details about the replicated VM (Figure A).
Limitations for VMware vSphere Replication
There are some things that vSphere Replication doesn't support, but that number is relatively small. The majority of the problems are just limitations that most can live without.
You can't replication ISOs and physical RDMs. This isn't too much of a problem in my opinion because it's a crazy idea to copy an ISO attached to the VM over a WAN. It's also important to note that template VMs, linked clone VMs (VDI) and VMs with Fault Tolerance enabled are not supported.
VMware vSphere Replication does not replicate VMs that are powered off and there is no automated failback of VMs -- it has to be done manually. There is also no replication of a snapshot hierarchy.
How does vSphere Replication compare to the competition?
How to fix issues with vSphere Replication
Figure out why there are issues with RPO times