In the Messaging system, the following failovers can occur:
Application server failure: Users experience intermittent percolation as there is an attempt to synchronize the cache data specifically voice messages, and that times out and causes the delay as one of the application server is down. Administrative actions like Password Update, User Greeting Update will also fail as the data synchronization between application servers fails. Calls to the server that is down will experience fast busy.
Storage server failure: The system goes into offline mode. In offline mode, administrative updates are not allowed.
Storage and application server failures: Administrative actions are not allowed and the Messaging system only allows leaving voice messages.