Question
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How to Remove a PowerHA Configuration?

Answer
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First decide which node will be removed. Once the node to be removed has been decided; then, proceed with the following steps.

1 – stop the cluster on both nodes
# smitty clstop

2 – export the volume group on the node to be removed
# exportvg vgname

3 – remove the disks on the node node to be removed
# rmdev -dl hdisk# or rmdev -Rdl fcs#

4 – remove PowerHA System Mirror (formerly known as HACMP) from both nodes
# smitty hacmp -> Extended Configuration -> Extended Topology Configuration
# smitty hacmp -> Extended Configuration -> Extended Topology Configuration -> Configure HACMP Persistent Node IP Label/Addresses -> Remove a Persistent Node IP Label/Address
# smitty hacmp -> Extended Configuration -> Extended Topology Configuration -> Configure HACMP Communication Interfaces/Devices -> Remove Communication Interfaces/Devices
# smitty hacmp -> Extended Configuration -> Extended Topology Configuration -> Configure HACMP Networks -> Remove a Network from the HACMP Cluster
# smitty hacmp -> Extended Configuration -> Extended Resource Configuration -> HACMP Extended Resources Configuration -> Configure HACMP Applications Servers -> Remove any application servers, application monitors and other resources that were configured
# smitty hacmp -> Ex tended Configuration -> Extended Resource Configuration -> HACMP Extended Resources Configuration -> Configure HACMP Service IP Labels/Addresses -> Remove Service IP Label(s)/Address(es)

– Remove any other resources that were configured
# smitty hacmp -> Extended Configuration -> Extended Resource Configuration -> HACMP Extended Resource Group Configuration -> Remove a Resource Group
# smitty hacmp -> Extended Configuration -> Extended Topology Configuration -> Configure HACMP Nodes -> Remove a Node in the HACMP Cluster
# smitty hacmp -> Extended Configuration -> Extended Topology Configuration -> Configure an HACMP Cluster -> Remove an HACMP Cluster
# smitty remove -> remove all of the PowerHA software, all filesets start with the word cluster. The software needs to be removed from all of the nodes that were part of the cluster

The shorter to remove the cluster configuration way is just to remove the cluster:
# smitty hacmp -> Extended Configuration -> Extended Topology Configuration -> Configure an HACMP Cluster -> Remove an HACMP Cluster

5 – Clean up any HA configuration in files such as /etc/hosts.
6 – Configure the network interfaces to have the correct IP addresses. Run smitty chinet to set the correct IP address.
7 – Unmap and rezone the LUNs so that they are only zoned and mapped to one node
8 – Remove any PowerHA related scripts from the removed node.
9 – Verify the run levels in /etc/inittab, they may need to be changed; especially, if running older versions of HA.
10 – Change the filesystems’ mount attribute to automatically mount on reboot through smitty chfs.
11 – If there were any NFS-defined filesystems, can go into smitty NFS to set the filesystems to be eported or mounted at boot time.

If there were NFS cross mount filesystems configured where the local mount point has a different name than the NFS mount point; then, the local mount point will need to be renamed the same as the NFS mount point.
Use the smitty chfs command and set the local mount point to be mounted ONLY JFS at system restart on the local node, and ONLY NFS at system restart on all remote nodes.

12 – Configure your application to start at system restart if necessary.

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