Cisco Unity Deployment and Solutions Guide

Unity System Features 255

As you can see, a Unity administrator has a number of tools and features at his disposal to

administer, maintain, and secure a Cisco Unity server. It is recommended that each feature

be explored in further depth, with hands-on experience, to determine how it might help with

the administration of a Unity system. Managing a Unity server can be a complicated task,

especially considering all of the different technologies involved. The features and tools

described in this section were developed to make this job easier.

Unity System Features

A number of Unity features were mentioned in previous sections, but they need a more

detailed description to clearly identify their role. Unity subscribers and administrators

indirectly use other features, so these are difficult to describe in the context of a user. This

section is devoted to describing Unity features that operate at the system level.

Unity Failover

Unity failover provides customers with a simple redundancy solution so that call processing

and voice-messaging services can continue even when one Cisco Unity server fails or is

down for maintenance. Failover is a two-server solution, with one Unity server as the pri-

mary server and a second Unity server as the secondary server. Only one of the two servers

is active at a given time. The active server handles calls, takes messages, and is used to make

changes to Unity data. The inactive server is synchronized with any changes made on the

active server by means of SQL replication and file replication (file replication does not

occur if failover servers are set to manual mode—more on this later).

SQL replication ensures that whenever a Unity object is added, modified, or deleted, the

change is mirrored on the inactive server. File replication ensures that greetings, voice

names, messages and other data are replicated from the active server to the inactive server,

ensuring that this data is not lost. The administrator can configure the frequency of this file

replication. Not all Unity data is replicated between servers, so some changes need to be

made on both servers (for instance, Registry changes via the Advanced Settings tool). The

Failover Configuration Wizard is provided to simplify the process of setting up failover

between two Unity servers. However, it should be noted that the voice-mail ports on the

phone system need special configuration when failover is used, to ensure that calls and call

information properly are delivered to both primary and secondary Unity servers.

Failover can run in either automatic mode or manual mode. When failover is configured for

automatic mode, the primary server fails over to the secondary server when a problem

occurs on the primary server. Automatic failover occurs without user intervention. Prob-

lems that might induce failover include complete Unity system failure, calls not being han-

dled on the primary server, and loss of network connectivity on the primary server. The time

that it takes to fail over in any of these situations depends on the settings used for failover

and the system configuration, but, on average, it takes less than 1 minute.