IVM to HMC Migration - a Customer's Experience
AnthonyEnglish 270000RKFN Visits (6904)
The IVM or Integrated Virtualization Manager, is a browser interface to the VIO server on smaller systems, and it has HMC-like functionality, such as Dynamic LPAR, the ability to configure LPARs, stop and start them and so on.
The HMC (Hardware Management Console, as you know) is able to manage several physical servers and is mandatory for larger systems. It can also be used for smaller systems, and is a worthwhile investment, in my view, once you get beyond a single small server.
Two servers, two IVMs
I had a client who had bought a production Power6 550 and a P6-520 for Dev and Test. After some months of discussion, their Business Partner convinced them of the benefit of investing in an HMC to manage these two systems with their growing number of LPARs. The challenge was migrating each of the servers from being IVM-managed to the HMC. I have put together a document of my own experience of the migration. It doesn't attempt to be a step-by-step guide. More of a diary for my own benefit but you may find it useful.
Forward planning brings us unstuck
We thought we were being safe by getting some work done ahead of the outage time. We racked and cabled the HMC and put it on the network, in preparation for the scheduled outage two weeks hence. Problem was, no one told the HMC the planned go live date. To our surprise, it immediately discovered the two servers. At the same time, the HMC was reporting the two servers were in "Recovery" state, but it wouldn't take further control of the systems or their LPARs until the outage which was scheduled for after a huge month end. The IVM had been effectively disabled, so any IVM-specific commands were out of bounds. No profile backups, no DLPAR, no shutdown and activation of LPARs was permitted, either from the IVM or from the HMC. Nothing would undo it - not even powering off and disconnecting the HMC from the network.
We had a VIO server, but no IVM and no HMC that we could do anything useful with. It was the technological equivalent of a hung parliament.
All's well what ends well
In the end, it all worked, and the customer has been running happily on the HMC for many months now. Still, it was a challenge. You can find my comments about the migration from IVM to HMC Migration - A Customer's Experience
Looking back, it was quite funny, I suppose. As long as you weren't me.