To update or change the IP address on GPFS cluster (AIX & Linux)

To update or change the IP address of nodes in a GPFS cluster, the general process involves several key steps:

Prerequisites:

• Root or equivalent privileges all the GPFS nodes.
• Confirm all nodes are reachable via SSH new IP address.
• Ensure there’s a maintenance window (since GPFS services will be stopped).
• Backup critical configuration files.

1. Backup Existing Configuration Files

Run these commands on the primary node:

# cp -rp /var/mmfs/gen/mmfsNodeData /var/mmfs/gen/mmfsNodeData.org

# cp -rp /etc/hosts /etc/hosts.old

# cp -rp /etc/filesystems /etc/filesystems.pciip

This preserves the original configuration in case a rollback is needed.

2. Unmount and Stop GPFS Cluster

Unmount all GPFS filesystems and shut down GPFS services:

# mmumount all -a

# mmshutdown -a

Check that all nodes are properly shut down:

# mmgetstate -aL

Expected output: all nodes should show down.

3. Update Host IP Addresses

Edit the /etc/hosts file to replace the old IPs with the new ones.

# vi /etc/hosts

Before:

192.168.10.101   node1

192.168.10.102   node2

After:

# 192.168.10.101   node1

# 192.168.10.102   node2

192.168.10.151   node1

192.168.10.152   node2

qw! Save and close the file.

4. Update GPFS Node Interfaces

Use the mmchnode command to change the admin and daemon interfaces for each node:

# mmchnode --admin-interface=node1 --daemon-interface=node1 -N node1

# mmchnode --admin-interface=node2 --daemon-interface=node2 -N node2

Verify the change:

# mmlscluster

Confirm the new IPs are correctly associated with the nodes.

5. Restart GPFS Cluster

Start GPFS on all nodes:

# mmstartup -a

Check the state again:

# mmgetstate -aL

Expected output: all nodes should show active.

6. Verify Filesystem Mounts

Remount all GPFS filesystems:

# mmumount all -a

Then verify mount points and disk space for AIX:

# df -g or df -g <filesystem_name>

Then verify mount points and disk space for Linux:

# df -h or df -h <filesystem_name>