Sort of a basic question. But, I have 8 sites, same organization, each with a WLC. All sites are connected on the same network. Is there any advantage to placing them all in the same mobility group? Roaming from site to site is not done often. The goal is to try and reduce administration. Can SSID's be centrally managed if all in same mobility group?
The best design in this case would probably be to use different mobility domain names in each site, and only add controllers to each other's mobility group list if it was needed for auto anchoring.
By adding WLCs to each other's mobility group list, they will then start sending mobility messages between each other. If there is no possibility of roaming between controllers (or auto anchoring), then these messages are pointless to share.
Also, if you do need to add WLCs to each other's mobility group list for auto anchoring purposes, using different domain names is important. Otherwise, you run the risk of APs discovering and joining to wrong controllers.