Just a quick note: if you plan to apply PSU 5 on top of 220.127.116.11 on AIX 6.1 or 7.1 – it has a known issue.
CSSD will not start on the second node (depending on the order how you start OHASD in the cluster) and ocssd.log will show “gipchaLowerRecv: invalid message header hdr” with broken multicast headers. It’s a little bit strange, because it could use broadcast as well (since 18.104.22.168), but I don’t know the background yet.
The known issue is:
Bug 16268804 : GI STACK NOT STARTING ON POST APPLY OF 22.214.171.124.5 PSU
So just be careful and look at this bug before you start. Up to now there’s no progress, the official workaround today is “Go for PSU 4 instead”.
Salute the brave