Backup Options. For any production Hyper-V environment, I suggest obtaining *.vhd image backups of the virtual server guests. These image backups greatly simplify the disaster recovery process. You don't have to worry about reinstalling any applications in the virtual server guests. Some backup options even let you perform granular restores from the *.vhd images, although typically these backup images have to be stored on disk (not tape) in order to perform a granular restore. If you plan to use this method, make sure you have adequate disk space for your *.vhd images. Even though these backups are initially stored to disk, you should still eventually copy them to some type of offline media like tape. Some of the backup options available with Hyper-V are listed in this TechNet blog. If you've ever had to recover a DC, or a SQL Server or Exchange Server installation from scratch, you know that the process is stressful, complicated, and time consuming. If you have a backup of the *.vhd disk images for the failed server, you can simply restore these images and start the machine. If your *.vhd image backup does not contain the latest data backup, you might have to perform a data-only restore to your virtual server guest, but having the *.vhd images greatly simplifies the recovery process.
Physical to Virtual (P2V) server migrations. There are quite a few tools that allow you to migrate from a physical server to a virtual server. In general, these tools work fairly well, however the migrated machine will only be as stable as the original physical server. If the server has been in service for any length of time, I suggest you rebuild the server from scratch from a Hyper-V Virtual Server Guest template and just migrate the data. This is similar to the situation of upgrading a workstation from Vista to Windows 7. Most IT professionals agree that the migrated workstation will be more stable if you wipe the hard drive and perform a clean install of Windows 7, rather than performing an in-place upgrade. The same rules apply to a virtual environment, except the exposure is significantly greater because you're dealing with a server, not a workstation. However, I have performed P2V migrations successfully under the following conditions:
- The physical server had not been in service very long, and I could vouch for its stability.
- The software necessary to rebuild the physical server is not available and the physical server hardware is in danger of crashing because of its age.
If you have the luxury of building the server from scratch in a virtual environment, take the extra time to do so. The server will be more stable, and you'll have fewer problems in the future.
The Live Migration feature in Hyper-V Server 2008 R2 has positioned Hyper-V as a production-ready virtualization platform. As with any newer technology avoiding the pitfalls will ensure a successful Hyper-V implementation. I hope this article helps you avoid any potential annoyances.
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