This section describes the process of modifying a Universal Messaging Cluster into a Universal Messaging Cluster with Sites. Clusters with Sites allow a standard Universal Messaging cluster to operate with as little as 50% of the active cluster members (as opposed to the standard 51% quorum in effect for clusters without sites), and provides administrators with a mechanism to prevent the split brain scenario that would otherwise be introduced when using exactly half of a cluster's realms.

The Enterprise Manager's top level view shows a tree node labelled Universal Messaging Enterprise. One level below this is a tree node labelled Clusters, which contains any known clusters.

After creating your cluster (see Creating a Cluster) and selecting the cluster's icon in the Enterprise Manager, click the Sites tab:

Click the New button to create the first site. We'll assume the site is named Production. Follow the prompts and pick a Realm to include in the site, for example realm1:

At this point, the new site will appear in the Sites tab:

Note that the table will contain a column for all realms in the cluster. In this example we have only added one realm to the Production site. Checking and unchecking the appropriate checkboxes will add or remove clustered realms from the corresponding sites.

Next, follow the same steps to create the second site, which in this example we shall assume is named : Disaster Recovery

The new Disaster Recovery site will now also appear in the Sites tab:

Administrators use a site's isPrime flag to determine the site that will contain a cluster's master realm.

We recommend you to make the production site the prime site. For a discussion on the pros and cons of whether to make the production site or the disaster recovery site the prime site, refer to the section Clusters with Sites .