I would suggest putting all the single sign-on functionality needs into a business requirement document that is specific to your company and making sure there are a robust set of tests throughout the project to ensure the servers retain all of their single sign-on capabilities. A good way to determine appropriate test criteria is to find your documentation set from the original SSO implementation by pulling your business requirements document, your technical requirements document and your SSO testing data. Review it to make sure that it still makes sense for the business and use the language and test steps from them to make sure virtualizing the servers won't have any negative effects on the business.
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This was first published in February 2009