Managing the cluster topology

These topics describe how to reconfigure the cluster topology.

Reconfiguring a cluster dynamically
When you configure a PowerHA® SystemMirror® cluster, configuration data is stored in PowerHA® SystemMirror®-specific object classes in the Configuration Database (ODM). The AIX® ODM object classes are stored in the default system configuration directory (DCD), /etc/es/objrepos.
Viewing the cluster topology
When you view the cluster topology, you are viewing the PowerHA® SystemMirror® Configuration Database data stored in the DCD, not the data stored in the ACD.
Managing communication interfaces in PowerHA SystemMirror
This section describes the options under the System Management (C-SPOC) > Communication Interfaces SMIT menu.
Adding PowerHA SystemMirror site definitions
You can define sites in PowerHA® SystemMirror® Standard Edition or PowerHA® SystemMirror® Enterprise Edition. You must define sites to enable PowerHA® SystemMirror® Enterprise Edition storage replication support, including Geographic Logical Volume Manager (GLVM) and Metro Mirror.
Changing the host name for a cluster node in PowerHA SystemMirror 7.1.2, or earlier
You cannot change the host name of a cluster node after the cluster is configured. To change the host name of a cluster node, you must first remove the Cluster Aware AIX® (CAA) cluster definition, update PowerHA® SystemMirror® and the AIX® operating system configurations, and then synchronize the changes to re-create the CAA cluster with the new host name.
Changing the host name for a cluster node in PowerHA SystemMirror
You can use PowerHA® SystemMirror® to change the host name for a node while cluster services are active.
Changing how PowerHA SystemMirror 7.1.3, or later, responds to host name change
Cluster Aware AIX® (CAA) uses the host name of a cluster node as a point of contact for cluster communications. PowerHA® SystemMirror® stores the host name information for each node in the configuration database. If the host name of a cluster node changes, you must update the host name information in the PowerHA® SystemMirror® configuration database.
Changing the IP address for a PowerHA SystemMirror cluster node
When you change the boot IP address, a cluster outage might occur. Therefore, you need to plan your downtime.
Changing a cluster name
Changing the name of a cluster is allowed only prior to initial synchronization of the cluster configuration in PowerHA® SystemMirror®. After you have synchronized the initial cluster configuration, you cannot change the cluster name. Instead, you must remove the cluster completely and recreate it.
Changing the configuration of cluster nodes
As the system administrator of a PowerHA® SystemMirror® cluster, you may need to perform any of several tasks relating to cluster nodes.
Changing the configuration of a PowerHA SystemMirror network
You can change network attributes, but you cannot change them dynamically.
Changing the configuration of communication interfaces
As a system administrator, you may need to perform several different tasks relating to cluster network interfaces.
Managing persistent node IP labels
This topic describes different tasks for managing persistent node IP labels.
Synchronizing the cluster configuration
Whenever you modify the cluster definition in the Configuration Database on one node, you must synchronize the change with the Configuration Database data on all cluster nodes.
Dynamic reconfiguration issues and synchronization
These topics are relevant for dynamic reconfiguration of both topology and resources.

Parent topic: Administering PowerHA SystemMirror