Unity Connection Cluster Overview
Unity Connection supports a cluster configuration of two Unity Connection servers to provide high availability and redundancy. The Unity Connection servers handle calls, HTTP, and IMAP requests. If only one server in the Unity Connection cluster is functioning, the remaining server preserves the system functionality by handling all calls, HTTP requests, and IMAP requests for the Unity Connection cluster. Note that each server in the Unity Connection cluster must have enough voice messaging ports to handle all calls for the Unity Connection cluster.
The first server installed is the publisher server for the Unity Connection cluster; the second server installed is the subscriber server. These terms are used to define the database relationship during installation. The separation of roles is consistent with the Cisco Unified Communications Manager cluster schema in which there is always one publisher server and multiple subscriber servers. (Note that Unity Connection runs on the Cisco Unified CM platform). Unlike a Cisco Unified CM cluster, however, Unity Connection supports only two Unity Connection servers in the Unity Connection cluster.
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It is recommended to perform provisioning only on the Publisher server in Active-Active mode and on Subscriber (Acting Primary) in case of cluster failover. The password change and password setting modification for User PIN/Web application should be provisioned on Publisher server in Active-Active mode. |
For a network diagram of a Unity Connection cluster integrated with Cisco Unified CM, see Figure.
A Unity Connection cluster server pair supports up to 20,000 users. In this configuration, both servers can support up to 250 voice messaging ports each for a cumulative total of 500 voice messaging ports when both servers are active. If only one server is active, the port capacity is lowered to a maximum of 250 ports.
For more information on capacity planning for a Unity Connection cluster, see the Cisco Unity Connection 14 Supported Platforms List at https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/14/supported_platforms/b_14cucspl.html.
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A Unity Connection cluster server pair supports up to 20,000 IMAP Idle clients (250 sessions).If the IMAP clients that connect to the Unity Connection server do not support IMAP Idle, each of these clients must be counted as 4 IMAP Idle clients. For example, deploying 4 non-IMAP Idle clients is the same as deploying 16 IMAP Idle clients. |