Cluster system architecture flow

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When you use Cluster Aware to create a cluster it is important that you understand the process of the clustering subsystem.

Note: Cluster Aware AIX® (CAA) is not used as a stand-alone package. It is used with PowerHA SystemMirror or with Shared Storage Pool. PowerHA SystemMirror or Shared Storage Pool describes how to create a CAA cluster through its own commands. Refer to these products’ respective documentation, including IBM® Redbooks® publications and release notes.

The following list describes the process of the clustering subsystem:

  • The cluster is created by issuing the mkcluster command.
  • The cluster configuration is written to the raw section of the cluster repository disk.
  • Special volume groups and logical volumes are created on the cluster repository disk.
  • Cluster file systems are created on the special volume group.
  • Cluster services are made available to other functions in the operating system, such as Reliable Scalable Cluster Technology (RSCT) and PowerHA SystemMirror.
  • Storage framework register lists are created on the cluster repository disk.
  • A global device namespace is created and interaction with LVM starts for handling associated volume group events.
  • A clusterwide multicast address is established.
  • The node discovers all of the available communication interfaces.
  • The cluster interface monitoring starts.
  • The cluster interacts with Autonomic Health Advisory File System (AHAFS) for clusterwide event distribution.
  • The cluster exports cluster messaging and cluster socket services to other functions in the operating system, such as Reliable Scalable Cluster Technology (RSCT) and PowerHA SystemMirror.