As someone wise once noted, when swinging through the trees, Tarzan didn’t let go of the last vine before he had grasped the next one. It goes without saying that it’s critically important to test a migration before performing the migration. You don't want to find yourself swinging through the air while being unsure about the wisdom of grabbing the next vine.
You can use a test environment as a way of not only checking how well your migration plan functions when tested against an actual operating system and applications. It will also allow you to make an assessment about the hardware requirements for that workload.
For example, you might assume that you can migrate certain workloads into a virtual environment, and have an idea what the hardware capabilities of that final virtual environment will be. But when you run the test migrated workload in a test environment, you may discover that your assumptions are “out of whack”.
When thinking about your migration test environment, remember that you can perform testing in a piecemeal fashion. In most cases you’ll be bringing over one workload at a time from Server 2003 to Server 2012 or Server 2012 R2. This means that you can test one workload at a time in the test environment rather than testing all aspects of the migration at once.
In the next post, we’ll talk more about what makes a good migration test environment.