I purchased a Mac Mini Server last July. I've had problems with the system going catatonic and stops responding. The only recourse is to power cycle the system. So far I have been unable to find anything in the logs that would provide an indication what may have triggered the condition. I am using the second drive as a backup device for Time Machine. The Mac Mini Server is more likely to go catatonic whenever Time Machine periodically does a full backup. At least I think it is doing this as it sends data for several days instead of a small amount of data every hour. The periods of catatonia generally occur sometime between 1500 and 1830. The Mac Mini Server is headless and a generally keep Server Admin and/or am logged into the server using Screen Sharing.