3.2 Using Cluster Best Practices

Using the following cluster best practices can help you avoid potential problems with your cluster:

  • Ensure that eDirectory is stable before implementing a cluster.

  • Ensure that you have full Read/Write replicas of the entire eDirectory tree co-located in the data center where you are setting up the cluster.

  • Ensure that IP addresses are unique.

  • Consistently apply IP address assignments for each cluster and its cluster resources.

  • Make IP address changes for the cluster and cluster resources only by using the procedure described in Section 8.13.2, Moving a Cluster or Changing IP Addresses of Cluster Nodes and Resources.

    IP address changes for cluster resources should always be made on the Protocols page of the iManager Clusters plug-in, not directly in load, unload, and monitor scripts. This is the only way to change the IP address on the virtual NCS:NCP Server object in eDirectory.

  • Ensure that Volume IDs used for a cluster resources are unique across all nodes.

    Each cluster node automatically assigns volume ID 0 to volume SYS and volume ID 1 to volume _ADMIN. Cluster-enabled volumes use high volume IDs, starting from 254 in descending order. Volume IDs can be assigned in the cluster load script. You can view the volume IDs assigned on a node by using the ncpcon volumes command.

    The Client for Open Enterprise Server uses the volume ID to access a volume.

  • Consider each node’s configuration requirements for each of the services it is intended to host.

  • Create failover matrixes for each cluster resource so that you know what service is supported and which nodes are the preferred nodes for failover.