Nirvana Enterprise Manager - Creating and Managing Clusters with Sites

This section describes the process of modifying a Nirvana Cluster into a Nirvana Cluster with Sites. Clusters with Sites allow a standard Nirvana Cluster to operate with as little as 50% of the active cluster members, 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.

Viewing Site Information in Enterprise Manager

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

After creating your cluster and selecting the cluster's icon in the Enterprise Manager, click the Sites tab:

Sites Tab in Cluster View. No Sites have yet been created for the above cluster.

Creating a Primary Site for a Cluster

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 as follows:

Creation of a "Production" Site and addition of an initial Site member realm.

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

The "Production" Site with its initial member realm is shown.

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.

Creating a Backup Site for a Cluster

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

Creation of a "Production" Site and addition of an initial site member realm.

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

Sites Tab in Cluster View. The "Production" and "Disaster Recovery" Sites are both shown.

Setting a Site's IsPrime Flag

Administrators use the Sites isPrime flag to determine which site will contain a cluster's Master realm. Typically, the Production Site will be set to be Prime. Should the Production site fail, the administrators would set the Disaster Recovery Site to be Prime, which permits the election of a new Master without the usual 51% quorum requirement:

Setting the Production Site to be Prime by checking its isPrime checkbox.