Our support department gets a lot of questions about virtual machines and recently, a lot of these questions relate to backing up Hyper- V host machines and any virtual machines hosted on that machine. Here’s a quick guide to getting the most out of your host machine and virtual machine backups using StorageCraft ShadowProtect.
There are a few things you should consider doing to properly backup your Hyper-V host machines and ensure the integrity of your ShadowProtect backup images. To get the most out of your backup process you’ll want to back up your host machine and each virtual machine as well. Here’s how to do it:
1. Be sure that the virtual hard disk (VHD) is running on a separate volume from the OS system. This means you’ll have a system drive (we’ll call it C:) and a separate volume (we’ll call it V:) where your VHD is stored.
2. Having the VHD run from a separate drive will not only increase the performance of the machines, but will also make it possible to segregate your backup jobs, which will be useful in a moment.
3. Next, back up the entire system drive (C:) as one job.
4. Now run a separate backup job for data on the data drive holding the VHDs (V:). This will ensure you have a solid backup of your VMs and other critical data from the host level.
5. You should have the ShadowProtect VM client installed on each of the virtual machines. Be sure to run a backup job on each one*. This will allow you not only to monitor the VMs and see any ShadowProtect errors that may come up, but it also gives you the flexibility to restore any individual VM to a new host. Be sure to monitor your machines from a ShadowProtect management console (like the brand-new version of ShadowControl CMD) so you can see your host and virtual machines all at once.
6. Regularly check the virtual machines’ event logs for VSS errors as they can indicate problems with the backup. This is good to do because when the host machine calls for a backup of the VM, the VM is asked to pause processes while ShadowProtect takes the snapshot, but since this process has to go through the Hyper-V VSS writer, the VM may not always be in the perfect position to take the pristine images that ShadowProtect is known for. These errors will, however, appear in the VM event logs. By watching them, you can avoid any errors in your incremental chains.
It’s important to understand that the more lines of communications between the host and the VM, the more difficult it is to take a pristine backup. It’s always best to backup the host and each individual VM to ensure that you have everything backed up while maintaining flexibility and full support from StorageCraft.
* Remember, if any of the virtual machines don’t have a ShadowProtect license on/for it, StorageCraft can’t support it and therefore can’t guarantee the quality of the backups or help with troubleshooting.
Author Note: Special thanks to Kevin Steele and Steven Snyder for helping sort the technical mumbo jumbo.
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