Posey's Tips & Tricks
When Should You Back Up Server Operating Systems?
As with most things in the IT space, the answers will vary on your needs and how much free time you have.
One subject that has been hotly debated over the years is whether it is better to back up entire servers (operating system, applications, data, etc.) or if it is more prudent to simply back up the data and not worry about anything else.
Compelling arguments have been made on both sides, but an industry wide consensus has never been reached. Like so many other things in IT, my opinion is that there is no one size fits all answer to the question. You have to do what's best for your own organization. As such, I wanted to give you a few things to think about.
Reasons To Avoid Backing Up the Server Operating System
The biggest reason that is often cited for not backing up a server operating system is cost. Simply put, backups consume storage space and that storage space comes at a cost. It is worth considering that if you are deduplicating your backups, then only one physical copy of each operating system will actually be stored.
Another reason that is often given for not backing up server operating systems is that when problems occur, it is generally better to install a fresh copy of the operating system (by reimaging the system from a known good image) rather than trying to restore a backup of an operating system that was in an unknown state.
Reasons To Back Up the Server Operating System
Now that I have talked about a few of the more commonly given reasons for not backing up server operating systems, I want to talk about a few things that may justify a server operating system backup.
One such issue is that you might want to back up server operating systems if you don't have an easy way of deploying an operating system in the event that it should become necessary to do so. In other words, larger organizations tend to maintain a collection of operating system images. In the event that a problem occurs, a fresh image is simply pushed to the machine that is having problems. If, however, your organization does not have such a system in place, then your only option for deploying an operating system might be to break out the installation media and manually deploy the OS. While there is nothing wrong with this approach, it is time consuming and it opens the door for potential human error. If you're having problems with a mission-critical system, then it may be quicker and easier to get the system back online by restoring a backup rather than trying to manually deploy and configure the server's operating system.
Another situation that might justify backing up the server operating system is situations in which everything that is running on the server is extremely version specific. Several years back I had an application that I was using in my own environment that required a specific version of the .NET Framework and a specific version of Java. Because of these and other requirements, I, not surprisingly, had to run a specific Windows build on that machine. Had I upgraded to a newer Windows build, it would have almost certainly broken the application.
The reason why I mention this type of situation is because unless you just happen to have a copy of the exact Windows build that you need, it can be really difficult to get your hands on an older Windows release. Even using the Visual Studio download library might not be an option, as Microsoft frequently purges older software from the list of available downloads. That being the case, if you're running something older that would be hard to replace, then you should probably think about backing up the server operating system.
A third reason why you might want to back up a server operating system kind of ties back to the reasons that I have already given. You should consider backing up the server operating system if the operating system's configuration would be difficult to replicate. If your servers are running a relatively standard configuration that mostly adheres to your organization's defaults, then there may not be a pressing need for an operating system backup. If, on the other hand, you are doing something special that would be difficult or time consuming to reconfigure than a backup may be worthwhile.
In my own organization I have one particular server that maintains an iSCSI connection to a storage device. Even though iSCSI is normally really easy to configure, this particular connection just did not want to work. After many hours of effort, I found just the right combination of settings within Windows and within the storage array that would allow iSCSI connectivity to function. Given the difficulty that I had in setting up this particular server, I absolutely maintain a backup copy of the operating system (and a backup copy of my storage array's configuration).
About the Author
Brien Posey is a 22-time Microsoft MVP with decades of IT experience. As a freelance writer, Posey has written thousands of articles and contributed to several dozen books on a wide variety of IT topics. Prior to going freelance, Posey was a CIO for a national chain of hospitals and health care facilities. He has also served as a network administrator for some of the country's largest insurance companies and for the Department of Defense at Fort Knox. In addition to his continued work in IT, Posey has spent the last several years actively training as a commercial scientist-astronaut candidate in preparation to fly on a mission to study polar mesospheric clouds from space. You can follow his spaceflight training on his Web site.