We have a client that has 2 servers that they want to install Windows server 2008r2 enterprise on. On server 1, they will have 2008r2 enterprise installed with hyper-v and then 4 virtual servers. So, a single enterprise license handles that. On server 2, they want it for redundancy purposes in case server one ever crashes. They will restore the virtuals to this server. So, do they need a separate enterprise license for the redundant server? It will always be up and running just in case they need it. The reason that it has to be running is Acronis will run a backup on the main host and put the virtual servers backup files on the backup host so if the main host dies, I can start up the hosts on the backup server. THanks for your help.