Preparing to Install or Upgrade › Preparing to Install or Upgrade CA Service Catalog › System Architecture › Medium Architecture

Medium Architecture

The medium architecture expands the small architecture by implementing clustering and adding load balancers, as follows:

The medium architecture setup follows. Each mention of two clustered servers refers to two virtual computers that are clustered.

• Two clustered servers host CA Service Catalog.

  Note: If you are upgrading two or more CA Service Catalog computers, you can upgrade them in any order. The designation of a first (or primary) server applied to earlier releases but is no longer relevant.

• Two clustered servers host CA Process Automation.
• One or preferably two load balancers are the front ends to the clusters for CA Process Automation and CA Service Catalog, respectively. Both the CA Process Automation and CA Service Catalog clusters require a load balancer, which can be an existing instance. CA Process Automation and CA Service Catalog can share a load balancer.
• Two clustered servers host CA EEM. CA EEM is clustered but is not used with a load balancer. We recommend clustering CA EEM to provide failover protection. You use configuration parameters to connect CA Service Catalog and CA Process Automation with the CA EEM cluster. You can increase CA EEM performance by pointing each CA Process Automation domain server to different CA EEM servers.
• Two clustered servers host the DBMS.

  Note: You cluster the DBMS to improve throughput and responsiveness. Verify that you cluster your DBMS using a method that improves performance. For example, using an active-active database cluster can reduce performance, especially on write operations. For details about clustering your DBMS, see its documentation.

• Some virtual machine software uses scheduling algorithms that result in decreased performance when the number of CPUs increases. This performance loss is most noticeable when the virtual machines are sharing systems with other virtual machines that also have a lower number of CPUs allocated. Typically, in such cases, increasing the number of virtual machines in the cluster improves performance more than increasing the number of CPUs per virtual machine.

Note: You install and cluster CA Process Automation according to the specifications in the CA Process Automation documentation. Similarly, you install and cluster CA EEM according to the specifications in the CA EEM documentation.

The medium architecture can efficiently process a load of 11-50 catalog requests per minute. This architecture provides a good starting point for most implementations. You can monitor performance and you can add clustered instances, if necessary.

Consider the factors for moving from a small architecture to a medium architecture. The same factors in greater magnitude can cause you to move from a medium architecture to a large architecture.