11.02.06
What can Virtualization do for you?
Virtualization is the process of taking a physical server and turning it into a virtual server. A virtual server can then be run in a special environment where multiple virtual servers share physical memory and cpu. The process takes some time to master, but once you do, it reduces your cost of ownership on a server by quite a bit. The main problem with physical servers is space, they take up real (usually expensive) space. With a virtual server, you can pack multiple servers onto a single physical machine and save that space. It’s also handy to be able to deploy a virtual server to test things out before you do a widespread release. This applies to patches and software mainly, but it is nice to be able to load several different OSes, have them all running, and test things from each one.
The best benefit comes from the ease of maintenance after you virtualize. Once you have virtual servers running, administration becomes very easy. I use VMWare on the IBM Bladecenter. With this setup, you can log into the virtual server console, and control any of your virtual servers from a single software interface. This makes rebooting, and troubleshooting on multiple servers much easier than if you have to connect to each machine seperately, using the network, or even the local console (keyboard and mouse connected to the physical server). This means if you need to work with many servers, you save quite a bit of time if they are all virtual servers.
The main problem I run into while working with legacy physical servers is determining if they can be virtualized or if they must be migrated. Virtualizing entails running some software to get an exact copy of the physical servers hard drive, and transferring that image to a virtual machine with a virtual hard drive. This process means you inherit every problem that the physical machine may or may not have. The physical machine could have countless problems that aren’t apparent from a cursory inspection. A virus might be live on it, there could be legacy applications that hurt performance running in the background, or it could just have been initially setup incorrectly. Migrating a server entails installing a new OS into a virtual machine, and then installing the applications in use on the physical server, and finally moving the data from the physical server to the virtual server. Once you migrate a machine, most of the legacy issues I typically find in production go away. Knowing how to correctly do an initial OS setup in crucial to having a migration work correctly.
Virtualizing can bring many benefits to an Administrator’s day-to-day activities. Anything that can save you time will make you more effective when it comes to the things that matter. I highly recommend anyone interested in virtualization to get and install VMWare Server. It’s free for Windows and Linux, and can give you a small taste of the ease and effectiveness of Virtualization. I myself prefer the Linux version, because you can strip a Linux box down to bare essentials, you can make better use of the resources (cpu, memory) in your machine. The Windows version runs adequately, but Windows entails more overhead from the GUI than you might like on a virtual server. You can strip Windows down pretty well, but not quite as well as you can a machine running Linux. Windows forces you to use the GUI, and that is ram and cpu being used that could be better spent on a virtual machine.
The Enterprise level of VMWare Server is called VMWare ESX Server. ESX is very useful when you are going to use many virtual servers in production. I can attest it is the fastest, and easiest to use software of this level I’ve seen so far. It is expensive, but if you are going to be using virtual servers in production, it’s worth having. If you install multiple copies of ESX, you can aggregate the administration into a single interface using VMWare VirtualCenter. VirtualCenter connects to multiple ESX servers and allows you to administrate any virtual server on any ESX server from a common software interface. It’s quite powerful for large deployments of virtual servers, especially when you consider the cost of building the same sort of infrastructure for physical machines.
Virtualization can save you time and money. It can also simplify your daily administration and maintenance tasks. Using a single interface to control many machines is effective and efficient. You can easily modify and revert changes to virtual machines using the tools included with VMWare. I’ll get into that a little more in a later article, this one is for the “big picture” benefits. Patching, Rebooting, and remote trouble-shooting are all simplified on a virtual server platform, simply from having every machine “at your fingertips” so to speak. I cannot stress enough how much of a difference this makes in the amount of time I spend at normal administration. It has saved me literally weeks of time since I started using virtual servers instead of physical servers.
Virtualization is here to stay, and I’ll be blogging my various trials and tribulations as I learn to master this technology. I have quite a bit of experience with it already, but now I’m using the big tools, like ESX and VirtualCenter, rather than the smaller free versions. I’ve spent countless hours playing with VMWare Server and have found it to be the most robust, and easiest to use of the free solutions available. Don’t just take my word for it, download VMWare Server and try it for yourself.