When Not to Use Virtual Machine Snapshots
The following tip is excerpted from my book Training Guide: Installing and Configuring Windows Server 2012 from Microsoft Press:
Although snapshots are not recommended for use in production environments, they might have value in certain limited scenarios. For example, you might consider performing a snapshot of a production virtual machine just before you apply a critical software update to the guest operating system of the virtual machine. That way, if something goes wrong after applying the update, you can quickly revert to the virtual machine to its previous state (that is, before the update was applied). However, there are certain scenarios where you should never perform snapshots, specifically:
- Don't perform snapshots on virtualized domain controllers.
- Don't perform snapshots on virtualized workloads that run time-sensitive services.
- Don't perform snapshots on virtualized workloads that use data distributed across multiple databases.
Also, don't try to restore snapshots older than 30 days because the computer password for the guest operating system might have expired, which will cause the guest to dis-join itself from the domain.
Finally, if you do plan on performing snapshots, make sure the host has sufficient storage for all the snapshot files you might create. Snapshots can consume a lot of disk space, and you could end up running out of storage space if you perform too many of them.
The above tip was previously published in an issue of WServerNews, a weekly newsletter from TechGenix that focuses on the administration, management and security of the Windows Server platform in particular and cloud solutions in general. Subscribe to WServerNews today by going to http://www.wservernews.com/subscribe.htm and join almost 100,000 other IT professionals around the world who read our newsletter!
Mitch Tulloch is a twelve-time recipient of the Microsoft Most Valuable Professional (MVP) award and a widely recognized expert on Windows Server and cloud computing technologies. Mitch is also Senior Editor of WServerNews. For more information about him see http://www.mtit.com.