Types of Clusters

Types of Clusters

A resilient cluster consists of two or more Gateways that service clients and devices. A cluster that consists of Gateways of the same model is referred to as homogeneous cluster while a cluster that consists of Gateways of different models is referred to as a heterogeneous cluster. As a best practice, HPE Aruba Networking recommends deploying homogeneous clusters whenever possible.

Homogeneous Clusters

A homogeneous cluster is a cluster built with Gateways of the same model. The primary benefit of a homogeneous cluster is that each node provides equal client, device, and forwarding capacity along with common port configurations. This makes homogeneous clusters much easier to plan, design, and configure than heterogeneous clusters.

The maximum number of nodes you can deploy in a homogeneous cluster will vary by series. The 7000 or 9000 series Gateways can support a maximum of four nodes, the 7200 series can support a maximum of twelve nodes, and the 9100 or 9200 series Gateways can support a maximum of six nodes.

Heterogeneous Clusters

A heterogeneous cluster is a cluster built with Gateways of different models. Heterogeneous cluster support is primarily provided to help customers migrate existing clusters using older Gateways to newer models. For example, migrating an existing cluster of 7005 series Gateways to 9004 series Gateways or 7200 series Gateways to 9200 series Gateways.

The primary benefit of a heterogeneous cluster is that multiple Gateways models can co-exist within a cluster during a migration, however this comes with some considerations:

1. The maximum cluster size will be limited by the lowest common denominator Gateway series. For example, a heterogeneous cluster of 7200 series and 9200 series Gateways will be limited to a maximum of six nodes.

2. Base and failover capacities are extremely difficult to calculate. Active and standby client and device sessions will be unevenly distributed between the available nodes based on the capacity of each node. Careful planning must be performed to ensure that the loss of a high-capacity node does not impact clients or devices.

3. Forwarding performance, scaling and uplink capacities will vary between the nodes.

4. Configuration in Central may require device level overrides to accommodate uplink port differences between Gateway models.

While heterogeneous clusters are supported, they are not recommended for long-term production use. Heterogeneous clusters should only be implemented when migrating Gateways in existing clusters to a new model. If a heterogeneous cluster must be implemented, the cluster should be limited to two models of Gateways. While more than two Gateway models can be supported, troubleshooting and debugging will be more complicated if technical issues occur.