I own 1 SM Enterprise server license and maintain my subscriptions. It seems in reading the documentation in order to use failover, i.e. a secondary SM server you must own 2 x SM Enterprise licenses. This is contrary to how Exchange works in that you need Exchange Server with Software Assurance and you can now have a backup email server. It seems that if you license 1 SM Enterprise Server and maintain the subscription, i.e. the same as Software Assurance then you should be licensed to use SM Enterprise on a second server to work as a hot spare to the primary email server. Why is ST requiring TWO SM Enterprise license purchases when their model seems to be something presented as more cost effective than Exchange Server?