Where to start with virtualization? This is not a guide for anyone to follow to the letter, but more of an outline of what I have had experience with so far.

I started by looking at what is out there, so far there are three big players in the arena. VMWare, Citrix Xen, and Microsoft Hyper-V

They all have the same sales promises

• Lower Total Cost of Ownership (TCO)
• Power saving
• Integrated server management
• Scalability
• High availability 
• Green Computing

Total Cost of Ownership:
I happen to believe that this is one of the bigger lies for all the virtualization products. Yes you can run multiple operating systems on one physical machine, but the price of the underlying hardware is one of the lower costs on a server. You have licensing costs for the operating system, prices for the software you are planning on running on that machine, and prices to support that software those prices are not going to change, they might actually increase because you will be running more of them per server. Then you have the cost of administrating the virtual machines in honest man hours, who is going to train your support staff, how many hours will it take to set up the environment you want. After you get those costs centered, then you need to pay for the services you want in the Hyper Visor, like do you want just a High Availability, or the ability to actually move servers off ServerA to ServerB with little to no down time that is a higher cost. Also don’t forget to include the shared storage for having the ability to move live servers around, that isnt going to be something you want to skimp on. Over all the total cost of ownership for these products would be more expensive if you dont have a large number of machines. because what you are saving in hardware costs you are spending in licensing costs.

Power Saving/Green Computing:
This is one of the advantages that you get by switching to a virtual environment. If your virtual machines are not running at full tilt then they are using less CPU and less CPU means less of a power draw. You do get a savings here that can be equated to the all mighty dollar will a lower over all power bill.

Integrated Server Management:
This is where the magic happens. The Hyper Visor allows you to manage the virtual machines, from the BIOS level, meaning you don’t have to leave your chair to make low level changes. Or if you want to check the to see if a machine blue screened, you can see that from the console. Rebooting machines and getting into safe mode is just as easy as sitting in the data center, without all the noise.  It also allows you to make changes to the server almost on the fly. Things like adding RAM or adding a CPU can be done within 10 minutes. Also deploying a new machine can take as little as 15 minutes if you have a preconfigured master. That is from machine power on to ready for production. Everything you can configure on a physical machine can be configured here, within a few minutes.

Scalability:
With the ability to deploy servers quickly, a good admin/engineer can configure an environment that allows for servers to “active” during busy times, and “off” during slow times. Think about it, you have an application that has a peak time and a slow time. Instead of having resources sitting idle while things are slow, you can have them in an “off” state and use them only when needed. There is also the ability to overprovision with this setup though so you have to be thoughtful when designing the arena.

High Availability:
Server Uptime and SLAs need to be guaranteed, hardware is the number one cause of failure in any environment. Your software usually does not have issues, it is heavily tested and giving a green light by many people before you deploy it to the customer. If you take the hardware out of the list, or make it so the “hardware” can automatically “move” to another machine you can maintain those SLAs. All the Hyper Visor solution do have this offer. It is a glorious thing once it is setup and working. There are a few caveats to it but that is another storey.

This is only the first post with what to choose, and just gathering my thoughts on the subject before going deeper. Personally though I am liking the offerings from VMWare over Hyper-V and Xen, just because it is more of a standard at this point. VMWare has been doing this for a few years longer, and when I tried them back in the day, I did not like them. Now it has become a serious item and it works well.