One Active Voicemail Pro server
Server Edition supports one active Voicemail Pro server on the Server Edition Primary server. A backup Voicemail Pro server is supported on the Server Edition Secondary server for resiliency.
Dual Active Voicemail Pro servers
Server Edition deployments with Select licensing support two active Voicemail Pro servers, doubling the maximum channel capacity and dual processing locations. Each expansion system and all contained users can be configured to use one or the other. Each Voicemail Pro server provides backup for the other. The two Voicemail Pro servers are both active for a configured subset of users. They share a common configuration and message store. Each can support all mailboxes, message waiting indicators (MWI) and call flows under failure conditions.
The following configuration are supported.
Dual Voicemail Pro, each acting as a backup
Dual Voicemail Pro, no backup operation
Single master Voicemail Pro on Primary, no backup (non-Select)
Single master Voicemail Pro on Primary and backup on Secondary (non-Select)
Single master Voicemail Pro on Secondary and backup on Primary