I migrated a single 5.5 exhchange server to a 2000 cluster. I had them exsit in the same site and moved the users. Used the ADC and all that. I am using CA Brightstor Enterprise Backup on a SAN attach IBM 3583. What virtual memeory tuning were you talking about. I would really like to rebuild this cluster. I just don't trust it as my only production Exchange server.