Backing Up Virtualized Machines

As a Systems Administrator my customers rely upon me to put procedures in place that will allow them to recover from numerous types of failures. One of the biggest challenges is recovering from a Windows operating system crash. To mitigate this type of failure; I have used the technique of cloning the operating system periodically in conjunction with daily backups.

In the past I have recommended cloning of operating systems as a overall part of your backup and recovery strategy. If you have ever worked with the existing cloning solutions then you are aware that there are many drawbacks. The most notable is that cloning software and hardware RAID do not play well together. Then there is the issue of the time it takes to clone a system. These restrictions make the ongoing cloning of live systems virtually impossible.

By virtualizing your operating systems, not only can you maximize your hardware investment, you can also dramatically improve your overall backup and recovery strategy. It's really quite simple; you shutdown the virtual machine and make a copy of the files... tada!! you have just made a perfect backup of the entire operating system! (the amount of time that the operating system is down depends upon the size of the virtual machine and the speed of the hard drives on the host machine)

I have found that even on low-end hardware I can make a complete backup of the virtual machine in under an hour. (your milage will vary) Once the virtual machines are copied I just FTP them to a different machine for long term storage. I use this technique weekly to make (what I refer to as) low-level backups of critical virtual machines for my customers. Please note that this low-level backup of the entire virtual machine does not replace the need to have daily offsite file and database backups. This low-level technique is designed to allow System Administrators to quickly recover from failure and perhaps sleep a little better at night.

I am the most familiar with the VMware virtualization products. VMware software is a very mature and robust system that can be used to virtualize your operating systems. (their entry level products are free) It even allows for scripts to automate the entire process. While the ability to recover from a operating system crash within minutes or hours is a dream for a sysadmin and many different solutions exist, virtualization is the most cost effective solution that I am aware of.

So let me bottom line this; if you do not know about virtualization then its time to learn! It can make your life a lot easier.

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