[eraserhead]

I'm working with a customer who has a new P570 and an associated HMC. He already has another P570 and HMC, and we'd like to connect the old HMC to the second HMC port on the new 570 and the new HMC to the second HMC port on the old 570. My concern is that I understood that the two ports need to be on different networks and I rather suspect that the old HMC is using the (default) DHCP range. If I change one of the HMCs to use a different range, will the SPs obtain their address OK?

[FASherman]

The safest way to do this is to schedule an outage window for both p570s. Shut down all LPARs cleanly. Modify the HMC(s) to use separate DHCP subnets. Reset the service processor on both servers (the hole next to the power button that looks like one on a CD/DVD). Boot up the servers to partition standby. Verify connectivity/DHCP clients from HMC and restart partitions.

[steevojb]

Hi

You shouldn't have any problem with this. If required you could just assign static addresses to the asmi ports in 4's. old p570,new p570, old hmc, new hmc all on one subnet. The 2nd ports of each 570 on another subnet.

The asmi ports can be a bit temperamental when changing addresses though

http://publib.boulder.ibm.com/infoce...undanthmcs.htm


HTH

Steve

[eraserhead]

Thanks, all. I'll let the customer know. It looks like even if I'm lucky and the other HMC is using a different network, I still need the outage because the second port on both 570s looks like it's defaulted to the fixed IP.

[eraserhead]

Actually went through the process a couple weeks ago and everything went smoothly. I deleted the managed system on one of the HMCs (scary!), disconnected the cable to the service processor, and changed the DHCP range of the private network. I then reconnected (through a switch), and the managed system did not reappear. Oh no! I was able to manually add the managed system through the HMC menus. The trick is that the DHCP addresses are assigned from the top down. I picked the right address and the system appeared. It asked for the HMC Access password and all was OK. I then hooked up the other P570's HMC2 port to this HMC and voila! Redundant HMCs!

Notes:
1) before you do anything, access the ASMI menu and change the HMC Access password to something you know. You can also do this by right-clicking on the managed systme icon on the HMC.
2) it's possible the managed system would have reappeared if:
a) I had waited long enough, or
b) I had reset the service processor with the pinhole reset method previously mentioned. Manually adding resulted in no downtime, though.