How do you replicate VMware ESX Guest Machines from one ESX Server to another?

What is the vEssentials Suite?

While researching third party products for my new Train Signal VMware ESX Server video series, I spent some time with Vizioncore's product line. I was impressed at the breadth of products that they offer. They offer over 7 different virtualization products for VMware ESX Server. That is a larger virtualization product line than I can recall being offered by any other company.

vEssentials is one of their most popular bundles and it includes vRanger Pro. vRanger Pro is Vizioncore's most popular product. Also included in the bundle is vCharter and vReplicator. Here is a breakdown of the vEssentials product bundle:

• vRanger Pro - image-level HOT backups of VMware ESX Server guest operating systems. That backup can be done for the entire VM or just a differential of the VM. vRanger Pro provides a much needed backup GUI and it integrates with VCB and Virtual Center.
• vCharter - top-down performance monitoring of VMware ESX Servers with drill-down capabilities. vCharter provides alerting, reporting, capacity planning, and chargeback.
• vReplicator- replicates entire VMware ESX Server Guest virtual machines from one ESX Server to another. Only the changes to the Guest virtual disk are sent and those changes can be sent over a LAN or WAN. Replication can also occur if the hosts have dissimilar hardware and images can be sent from multiple machines to a single machine.

What is vReplicator and what can it do?

Let's say that, today, you want to replicate a VMware ESX Server Guest OS over to another ESX Server. What would you do? I suppose you could create a script that would snapshot the Guest VM then copy the entire Guest VM virtual disk to another ESX Server. However, how long would it take to create that? And why copy the ENTIRE guest virtual disk every night? That could be 10+ GB! And what if it was across a WAN? Truthfully, using a true replication solution is the only answer. Plus, after you see vReplicator in action, I believe you will clearly see that vReplicator is the best Virtualization replication solution available.

So what is vReplicator? vReplicator is host-level replication solution built just for VMware ESX Server & VMware Infrastructure. With vReplicator, you can replicate a VMware ESX Server guest OS (virtual disk) from one ESX Server to another. Once the initial replication is done, only the changes will be sent after that.

Here are some of the additional vReplicator features:

• vReplicator is easy to install on a centralized server
• There are no agent or clients that need to be installed on any of the ESX Host or Guest systems
• vReplicator only needs to be installed once and all virtual machines can be discovered by contacting each of the ESX servers.
• With vReplicator, you can copy multiple ESX Server Guest virtual machines from multiple ESX Servers to a single ESX Server. This is an excellent solution for disaster recovery.
• The hardware between the two ESX Server host systems does NOT have to be the same.

What does vReplicator look like?

vReplicator is a simple looking Windows application and its operation is easy. After telling vReplicator what ESX hosts you have on your network, all you need to do to replicate an ESX Guest OS from one ESX host to another is to select the source and destination.

Here is a screenshot from vReplicator, showing one of the new replication jobs I created:

As you can see, you can schedule the replication job to run every hour, day, or whatever time interval you want to specify. Additionally, you can "test" the job to see what the results would be. Full reporting of the results of all jobs that have been run can be found in the Reports section or if you watch a job run "live", you can see the results immediately.

In fact, here is what a running job looks like:

How does vReplicator work?

I know that I have already described how vReplicator works but let's take a look at a diagram:

As you can see, the vReplicator server sits in the middle. It contacts the Virtual Center server to set up snapshots of the ESX host systems. The vReplicator server then compares the differences between the virtual guest OS's on each ESX host and performs the replication.