Testing Disk Heartbeats

To test your disk heartbeats, you can look at the output of “cllsif” or “lssrc -ls topsvcs”, or you can actively test them. IBM provides a command to do this. First, find the devices associated with the disk HB VG, I’ll assume hdisk4 on nodeA and hdisk5 on nodeB.

HACMP timestamp inconsistent

If the timestamps between the nodes in a Concurrent VG get out of sync, you can get:
WARNING: The HACMP timestamp file for shared volume group: vg1
is inconsistent with the time stamp in the VGDA for the
following nodes: node1

Enable cluster encryption

For more security you can make your cluster use encryption for inter-node communication with no downtime.  Otherwise operations are allowed or rejected based on IP address, hostname, and the cluster rhosts file.  And, C-SPOC operations are not encrypted one of the important ones being password changes.  Possibly an even better option would be to create a IPsec VPN tunnel between nodes, but I haven’t tested that.

List available major device numbers

When creating HACMP concurrent volume groups, it’s necessary to sync the major device numbers between the nodes. To see what each node has available for major devices run:

lvlstmajor

Lazy Update – HACMP

On a multi-node HACMP cluster without enhanced concurrent VGs, anytime you add a LV to a volume group, you have to make sure the other nodes see the LV. This will also fix other VG out of sync issues. You can either take everything down and do an importvg on all the nodes, or you can do a “Lazy Update”: