Implementation Guide › Architectural Considerations › Architectural Use Cases › Clustered Components for Scale

Clustered Components for Scale

You can implement additional clusters to help performance levels remain high as you scale to extend throughput. This use case builds on the multiple components for operational continuity use case to explain how you can begin thinking about your architecture in terms of scale.

The initial deployment section of the diagram illustrates:

• A load balancer distributing user requests across multiple Agent clusters.
• Multiple Agent instances intercepting user requests for specific applications. Agents are configured to initialize and communicate with a primary Policy Server in the cluster. If enough Policy Servers in the cluster become unavailable, the Agents failover to another Policy Server cluster.

  Note: For more information about Agent and Policy Server redundancy and high availability, see Redundancy and High Availability.

• A Policy Server cluster evaluating and enforcing access control policies. Load is dynamically distributed between each Policy Server in the cluster.
• Multiple user store connections. Each Policy Server is configured to connect to a primary user store. The primary user store connection is configured with a secondary user store connection. The Policy Servers load balance requests for user information across both connections. If the primary connection becomes unavailable, Policy Servers failover to the secondary connection.

  Note: For more information about Policy Server and user store redundancy and high availability, see Redundancy and High Availability.

• A single policy store instance. Each Policy Server in the cluster connects to the same policy store for a common view of policy information. The primary policy store connection is configured with a secondary connection to which the Policy Servers can failover.

  Note: For more information about Policy Server and policy store redundancy, see Redundancy and High Availability.

  

Each component has a specific role with resource protection.

Note: For more information about the primary purpose of each component, see SiteMinder Components.

The Scaled for Capacity section of the diagram details another component block and illustrates:

• A load balancer distributing requests to the new Agent cluster.
• Multiple Agent instances intercepting user requests. In addition to their connections to Policy Servers in Cluster n, each Agent can also be configured to failover to any Policy Server in the environment. As illustrated by the dotted line, the Agents in Agent Cluster n are configured to failover to the Policy Severs in Policy Server Cluster 1.
• A Policy Server cluster evaluating and enforcing access control policies. As illustrated by the dotted line, each Policy Server cluster is configured with a failover threshold. When the number of available Policy Servers falls below the specified threshold, all requests that the failed Policy Server would otherwise service are forwarded to another cluster.

  Note: For more information about failover thresholds for Policy Server cluster failover thresholds, see the Policy Server Administration Guide.