A NetScaler cluster is a group of nCore appliances working together as a single system image. Each appliance of the cluster is called a node. The cluster can include as few as 2 or as many as 32 NetScaler nCore hardware or virtual appliances as nodes.

The client traffic is distributed between the nodes to provide high availability, high throughput, and scalability.

To create a cluster, you must add the appliances as cluster nodes, set up communication between the nodes, set up links to the client and server networks, configure the appliances, and configure the distribution of client and server traffic.

Prerequisites:

NetScaler appliances that are to be added to a cluster must satisfy the following criteria:

• A NetScaler cluster can only include NetScaler nCore appliances. Clustering of NetScaler Classic appliances is not supported.

• All appliances must have the same software version and build.

• All appliances must be of the same platform type. This means that a cluster can have either all hardware appliances (MPX) or virtual appliances (VPX) or SDX NetScaler instances.

  Note: Clustering of SDX NetScaler instances is supported in NetScaler 10.1 and later releases. To create a cluster of SDX NetScaler instances, see “Setting up a Cluster of NetScaler Instances”.

• For a cluster of hardware appliances (MPX), all appliances must be of the same model type.

• All appliances must be on the same network.

• All appliances must have the same licenses. Also, depending on the NetScaler version, there are some additional aspects to address:

  • For releases prior to NetScaler 10.5 Build 52.x:
    • A separate cluster license file is required. This file must be copied to the /nsconfig/license/ directory of the configuration coordinator.
    • Because of the separate cluster license file, the cluster feature is available irrespective of the NetScaler license.
  • For releases after NetScaler 10.5 Build 52.x:
    • No separate cluster license is required.
    • Cluster is licensed with the Enterprise and Platinum licenses. Cluster is not available for Standard license.

• Be initially configured and connected to a common client-side and server-side network.

Note: For a cluster of virtual appliances, that has large configurations, it is recommended to use 6 GB RAM for each node of the cluster.