Setting up a highly available environment is one thing, being able to support and maintain it another. To be quite honest, 80 percent of setting up a highly available messaging solution is all about planning; 20 percent of the effort is required to set it up. Maintaining the solution afterwards, requires 100 percent attention and effort. Exchange has come a long way and supporting high availability is no more than a fraction of what it used to be. In the following recipe we'll dive a little deeper into the maintenance mode of Exchange and explain how you can (temporarily) take an Exchange server out of service allowing you to troubleshoot, update or otherwise perform any action on it.