Promoting a Secondary Server to Primary

If you install multiple copies of Management & Control Services (MCS) on your network—creating a server cluster—the first server installed to the cluster acts as the primary server in the cluster, controlling how information is distributed between that cluster's servers.

If the primary server goes down unexpectedly, or you need to take the server down for regular maintenance, for example, you would need to "promote" another server in the cluster to take over the responsibilities of the primary server. The MCS Fail-Over function allows you to do so.

There are two ways you can use the Fail-Over function: from the MCS console, or by running the Fail-Over utility directly from any server in the cluster whose primary server went down. Normally, you would want to use the first procedure to perform this function. However, if the Management and Control Server goes down unexpectedly, the MCS console will no longer be accessible. In that case, you will need to use the second procedure. Refer to the appropriate procedure below for details:

Promoting a Server Using the MCS Console
Promoting a Server Directly

What Occurs When You Promote a Server

When you promote a server to the primary server in a cluster, the following events occur:

The MCS Fail-Over function queries each secondary server in the cluster for its database replication status and time stamp. It then determines the "best" database as the one with the latest time stamp between all of the secondary servers that reported a complete database.
The time stamp for each server's configuration database is provided by the primary server during normal server database replication, while each secondary server tracks its own replication status (either "In progress" or "Complete").
The Fail-Over function provides the name of the server with the "best" database to the server being promoted to primary.
The server being promoted replicates the data from the "best" database.
The new primary server modifies the database to reflect the cluster's change in primary server and then replicates the new database to each secondary server.

All of these steps occur when you click Promote to Primary during one of the procedures below.

To promote a secondary server to primary using the MCS console
In the MCS selection panel, point to MCS Functions and then click Server Management. The Server Management tree appears. In the Server Management tree, click Fail-Over. The Fail-Over page appears in the MCS management panel. In the Target Cluster list, select the name of the cluster to which the server belongs. If you only have one server cluster, the default cluster name (MCS Cluster) is listed. When you click the cluster name, the servers that belong to that cluster appear in the Target Server list. In the Target Server list, click the name of the server that you want to promote, and then click Promote to Primary. The selected server is promoted to primary, as described above. Promoting the server to primary automatically changes its priority to 0 (zero). In addition, events are added to the MCS event log indicating the success or failure of informing each server in the cluster of the change. For details on this property page, click Help in the upper-right corner of the page.

To promote a secondary server to primary using the MCS console

In the MCS selection panel, point to MCS Functions and then click Server Management.
The Server Management tree appears.
In the Server Management tree, click Fail-Over.
The Fail-Over page appears in the MCS management panel.
In the Target Cluster list, select the name of the cluster to which the server belongs.
If you only have one server cluster, the default cluster name (MCS Cluster) is listed.

When you click the cluster name, the servers that belong to that cluster appear in the Target Server list.
In the Target Server list, click the name of the server that you want to promote, and then click Promote to Primary.
The selected server is promoted to primary, as described above. Promoting the server to primary automatically changes its priority to 0 (zero). In addition, events are added to the MCS event log indicating the success or failure of informing each server in the cluster of the change.

For details on this property page, click Help in the upper-right corner of the page.

To directly promote a secondary server to primary

Enter the following URL in your Web browser:

http://servername/mcs/FailOver.html

where servername is the domain name or IP address of a server within the cluster for which you're designating a new primary.

If you run the Fail-Over utility on a server that belongs to the default MCS cluster (MCS Cluster), then you can access any server on any cluster on your network.

If you run the Fail-Over utility on a server that belongs to any cluster other than MCS Cluster, you will only be able to access the servers within that cluster.

If prompted, enter your user name and password to log on to MCS.
The Fail-Over page appears in the MCS management panel.
In the Target Cluster list, select the name of the cluster to which the server belongs.
When you click the cluster name, the servers that belong to that cluster appear in the Target Server list.
In the Target Server list, click the name of the server that you want to promote, and then click Promote to Primary.
The selected server is promoted to primary, as described above. Promoting the server to primary automatically changes its priority to 0 (zero). In addition, events are added to the MCS event log indicating the success or failure of informing each server in the cluster of the change.

For details on this property page, click Help in the upper-right corner of the page.


	Overview of MCS Server Clustering
	Installing a Package on a Server Cluster
	Manually Adding a Server to a Cluster
	Changing the Priority of a Clustered Server
	Removing a Server from a Cluster
	Renaming a Server Cluster
	Overview of Server Management