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HMC Enhanced GUI: A Cautionary Tale

October 23, 2018

Just in time for Halloween, here's a scary story involving the HMC enhanced GUI version and an inexperienced user.

As I understand it, an administrator was using the enhanced GUI to mount an .iso image that was stored in the organization's virtual media repository. The admin selected virtual storage. Then this individual selected a VIO server and clicked on Action/Manage Virtual Storage. This displays a window that says the VIO server is being queried. The window has multiple tabs, including virtual disks, storage pools, physical volumes, optical devices and virtual fibre channel.

At this point, the admin should have selected optical devices, which allows you to manage virtual optical media. Instead, the virtual fibre channel tab was selected; this brings up fcs devices. A device was chosen, and then the admin opted to modify partition connections. Now, if you're following along in your own HMC, be careful. The default is that all assigned connections are checkmarked, and there's a button that forces connection removal from running partitions. If you select that and click OK, all of the checked mappings are removed. It's a dynamic LPAR operation and everything is wiped.

And that's what happened. The admin for some reason ignored the warning message, and all of the NPIV mappings were removed from the VIO server. The adapter information was still in the saved profile, but the mappings were gone from the running profile. Fortunately this organization had dual VIO servers, so the client LPARs weren't affected, but it was a chore to recreate all of the mappings on that particular VIO server. (Given the lack of a change window, rebooting the VIO server wasn't an option.)

If you ever find yourself in this situation, you may be able to retrieve your mappings by shutting down the VIO server and restarting from the saved profile. But make sure you can rebuild the mappings from your virtual to physical adapters if necessary. Know which virtual adapters are mapped to which physical adapters, and keep the additional critical information that's needed to recreate your environment. Know the corresponding WWN numbers. Hopefully you're running hmcscanner regularly, and you should be backing up your VIO configs and VIO servers.

There's good logging on the new HMC code, which was helpful in this case. We were able to identify the user and the commands that were run.

In short, be careful. The enhanced GUI is still fairly new. Take the time to get used to it.

Posted October 23, 2018| Permalink