You'll want to make sure all of the applications you use will run in a virtual environment. In some cases specific software might just need its own server to run. Sometimes that just takes a rollout of the latest version of the app or a version that supports a virtual environment, although in other cases you might not be able to include it in your virtual environment, period.
All Your Eggs in One Basket
You do need to be aware of setting yourself up with a single point of failure. Especially consider this for your domain controller. If all of your virtualized domain controllers were on a single host and that host were to go down, you'd be without a domain controller. Be sure the deployment of a virtual environment doesn't leave you stranded high and dry if that environment were to fail.
Stemming from the last point, plan what you would do if the virtualized environment were to fail. A failure like this can cause heavy disruption on your network and cause widespread downtime. NetOps can help you plan this out so a failure has less impact.
In a virtual environment, application licenses can work a little different, in particular for Windows operating systems where in some cases you might not need a license for guest machines. Some software applications might have their own licensing structure for virtualized environments that you'll need to be aware of.
It's pretty likely you'll end up with some unused hardware once you are virtualized. You may find new uses for old servers or you may decide to retire them. If your old server hardware isn't that old, there are a lot of potential uses.
Looking to virtualize your servers to consolidate and better utilize your IT infrastructure? Give NetOps a call at 818.646.5200 and let us work with you to ensure the process goes smoothly.