How to: Hyper-V Replication for Immediate Disaster Recovery

In this article we show how to set up Hyper-V replication between two or more Hyper-V production servers, or from a production server to a backup server.

In fact, any combination is possible. Each server could replicate its own VMs elsewhere. In case of a failure you could simply boot the VM on the backup server.

The setup is depicted below and utilizes BackupChain backup software:

In our example, we have a VM called “Win7 on VHDX”. We want this VM to be copied to a disaster recovery server every night:

We first download BackupChain and as soon as the installation is finished, the Create New Backup Task wizard opens:

We select “Hyper-V Backup” and proceed:

The above screen is fine, we leave the ‘automatic’ option on and proceed:

The VMs on this server are shown above in a list. We now select the VM and proceed:

We select “I want to choose different settings” so we can adjust the default backup configuration:

In the above screen, we turn off deduplication and compression. We set “automatic cleanup” to 1. This means the destination server will only keep one copy of each VHD.

You could, however, increase that number and keep 2 or more copies. In that case, more space will be used and in case of a disaster you will be able to access the previous VM copy in addition to the latest copy.

Now it’s time to set up the backup target. The backup share is a folder shared on our disaster recovery server or backup server:

Select Network Folder and click Browse, then enter the disaster server network share details:

Note the above example uses a workgroup setting. “Disaster_server” is the network name of the server. The user name has been prefixed using the server name.

Note there are no double backslashes in the user name: disaster_server\admin

If you are using a domain, the prefix must be the domain name instead, for example: mydomain\admin

We then click OK and proceed to the next step:

If you like you can run the task immediately. In case you want to set up a schedule, click “Save Task and Edit”:

In the above screen shot, the tab “Schedule” was opened, where we can configure the task’s scheduled run time. The above example configures the task to run daily at 2:13 PM.

We then click “Run Backup Task” to run the task immediately, regardless of its schedule, for a test run.

Once completed we switch over to the Disaster Recovery Server. It’s F: folder is where we replicated our Hyper-V VMs for this example. The contents look like this:

By looking at the backup folder contents you can quickly verify how BackupChain replicated all VM files related to the VM you selected.

We now set up a “dummy VM” in Hyper-V on the Disaster Recovery Server and point the VM to use the VHDs created by BackupChain.

Create a new VM called “Replicated VM” and use a similar configuration for CPU and RAM as in the original:

The crucial step is to use the VHDX replicated by BackupChain:

The setup is now complete.

If you like to test it, run the VM on the Disaster Recovery Server (or Backup Server). Once tested, turn it off again so that BackupChain can overwrite the VHDX with the newest one next time it runs.

Summary

BackupChain may be configured to protect and backup your Hyper-V VMs in several different ways.

One popular strategy is to replicate Hyper-V virtual machines to a Backup Server, or Disaster Recovery Server.

In case of a production server failure, all you need to do is power up the VMs on the Disaster Recovery Server.

This is an efficient, reliable, and simple way to protect your Hyper-V infrastructure. Rather than relying on expensive SANs and complex Cluster Shared Volumes, a simple replication job eliminates the single point of failure.

Difference to Hyper-V Backups

Hyper-V backups are compressed and deduplicated. The downside is in case of a disaster a restore operation on the recovery server is required. The speed of a restore depends on CPU and hardware speeds and may take hours to complete for very large VMs.

Hyper-V backups, on the other hand, are very efficient with backup space usage. Each nightly backup requires only about 5 to 10% of the VMs size, when incremental deduplication is being used. The space required to replicate a VM 1:1 is hence enough for at least a week of Hyper-V backups.

Advantage of this Method Over Hyper-V Backup

By trading off storage space for immediate recovery, Hyper-V replication allows you to skip recovery operations altogether and boot virtual machines instantaneously.

Example Usage of Hyper-V VM Replication

• Replicate all Hyper-V hosts to a single Backup Server with a large storage device. Since it’s unlikely that more than one Hyper-V host will fail at a time, the Backup Server doesn’t have to be using better hardware than the production server. It only needs a larger set of hard drives
• Replicate each Hyper-V host to one another. By replicating VMs from A to B and vice versa, you don’t need to have a dedicated Backup Server, provided each Hyper-V host has additional disk space available.
• Use a Hybrid Backup Strategy by creating two backup tasks: one for replication and one for backups, perhaps with different targets.
  You could backup Hyper-V VMs with one task to a NAS device or a file server each night, say at 1 AM
  • At 3 AM another task could be run that replicates the VMs to the second Hyper-V production server you have, or a dedicated Backup Server.
  • In a small environment of just a couple of Hyper-V hosts, you could save on hardware and electricity costs by backing up and replicating each host to one another. All you need is additional hard disk space on each host, which would have to be a RAID

BackupChain Features

BackupChain isn’t just a virtual machine backup tool, it also covers your physical servers, too. As a Windows backup software it also offers cloud backup and Windows Server 2012 backup.
For virtual environments, VMware backup, VirtualBox backup, and Hyper-V backup (including CSV backup)
all support live backup and run using deduplication, which offers great storage savings when backups are taken as differential backup or incremental backup.
We also maintain a library of free software, such as DriveMaker, which maps an FTP site to a drive you can use from any application, including the command line.