A “CMS Cluster” is a group of Business Objects XI Central Management Servers (abbreviated CMS, which is a BO service\daemon) that are interrelated and connected so that they may work in conjunction to manage the various other BO servers and provide most of the basic functionality of Business Objects. Clustering them allows for greater capacity management (each Central Management Server can generally support about 500 to 600 concurrent users, based on usage) and fail-over capability. In other words, having a CMS cluster consisting of at least 2 CMS is a VERY intelligent design decision for any Business Objects XI environment requiring any fault tolerance.
Creating a CMS cluster is not too complicated, but for now outside the scope of this article. You should understand that pretty much every other BO service will benefit by being aware of this CMS Cluster. The cluster name is defined in the specifications of each server’s CCM configuration (BusinessObjects XI R2) or that of its Server Intelligence Agent (Business Objects XI 3.X). The way that the BO server is aware of the members of the CMS cluster is through server operating system registry key. The name and path of this key on the Windows OS is:
One thing important to note about this key is that it is self-maintained. If a CMS is joined or removed from the CMS Cluster than the other BO servers running on a node will communicate with the CMS Cluster and update the registry key to reflect the valid members of the CMS Cluster. Now this is not exactly real-time updating, but rather it occurs at start-up of the BO server (I mean a service, such as Web Intelligence Report Server) or even at enabling of a disabled server.
Reflecting on what I’ve just written I a reminded that it is a good thing to create a CMS Cluster that only contains one CMS. There are no negative impacts that I know of and this allows for scalability as you can easily add in a CMS to the cluster with this already configured.