Please Stop Changing Partition Profiles


The Enhanced HMC interface is here to stay.  If you are still changing partition profiles on your Power HMC, you really need to start using the new functionality instead, or you risk getting out of sync and losing changes.  It is painful to create a bunch of new virtual fiber channel adapters, and then have them magically disappear with your next reboot.  It’s even worse when you reboot a VIOS and choose an out of date partition profile and suddenly some of your client disks go away.  Ask me how I know.

I normally try to write articles focused on IBM i, but in this case, there really isn’t any difference between IBM i, AIX, and Linux.  All partitions (especially VIOS) should follow the same rules.


First a bit of history

IBM made the Enhanced HMC interface available as an option with version  If you were an administrator like me, you just looked at it once or twice, figured it didn’t make any sense compared to what you were used to, and just selected “Classic” from the menu when you logged in. 

Version V8R8.7.0 officially eliminated the Classic interface, but some enterprising users found and published a backdoor approach to access the classic interface even at that level (see Bart’s Blog - Enable classic HMC GUI on release V9R1 – referenced below) That unofficial approach was then shut down for good in May of 2020.

Why?  Because IBM is focusing development on a single easy to use interface that leverages DLPAR operations for all the new features like vNIC (see my previous blog post if that’s new to you).


Making the Move

First and foremost, make sure that your partition profiles are in sync with the running profile.

There is an excellent blog post in the IBM Community that explains this in much more detail.

If you are using VIOS, DON’T FORGET THE VIOS!  There is far more risk of lost configuration on VIOS than any other partition, because when you are using the Enhanced GUI, you are often making dynamic changes to VIOS you may not even be aware of.

The gist of it is that you should be running with the “Save configuration changes to profile” setting at “Enabled”.  If it is not currently set to enabled, you need to get it set that way.

If the setting is currently “disabled”, start by saving your current configuration to the default partition profile.  Select the partition view for the desired partition from the GUI, select Partition Actions->Profiles->Save Current Configuration and select the default profile name.  Most users only have one profile per partition.  If you are one of the few that has more than one, pick a name for the profile that you will use from now on.  The default name used for newly created partitions is “default_profile”, so that is pretty good choice for a name.   Save the configuration with the desired name.  If you created a new name, go into “Manage Profiles” for your last time and change it your newly saved profile as the default.  Now is also a good time to delete all those profiles you will not be using any more.

Now you can change the “Save configuration changes to profile” setting to “Enabled”.


Doing it the Enhanced way

Once you have this setting enabled, just stay away from “Manage Profiles” and make all of your changes using the Enhanced GUI dynamic menu operations available from the left-hand menu of the partition view. 

When you need to activate a partition that you previously shutdown, make sure you use the “Current Configuration” option rather than picking a partition profile.

The biggest difference between changing partition profiles and restarting with a different profile is that in the Enhanced GUI, it will make the changes dynamically on a running partition.  It will also make the corresponding changes on the VIOS, if necessary.  The days of keeping track of virtual port numbers can be gone, if you let them.

You’ll find that when you Google the procedure to do anything on the HMC, you will often find articles and screen shots that point you to modify the profile.  If at any point, one of these articles suggests using the Manage Profiles option or tells you to select a specific profile when activating a partition, keep looking for a new procedure.  You can often get good basic information from these articles, but the specific procedures are likely to get you into trouble.

Enhanced HMC changes are typically dynamic on a running partition.  This requires communication between the HMC and the running partition, which you will typically see referred to as an RMC connection.  One difference for the IBM i world is that IBM i uses a LIC connection rather than the RMC connections that are used by AIX and Linux.  This all means that you won’t see an RMC active flag on an IBM i partition.  I mention this for two reasons.  First, much of the documentation you will run into will mention the need for an active RMC connection for various procedures.  That is not true for IBM i.  Second, the O/S on an IBM i does need to be operating to make some dynamic changes.  The error message you’ll get while attempting to make some changes on an activated IBM i partition with refer to RMC, but it really means its not booted to a DLpar capable state. 

You may notice that there are things you cannot change using the Enhanced interface while the partition is active.  Some examples are max processor, max memory, max virtual adapters, and processor compatibility mode.  All these options require a shutdown and restart.  You will be permitted to make the changes while the partition is shutdown.

Why is it so slow? (Spoiler - it's not)

You might not believe me here, but it isn’t slow.  It just feels that way because it is doing everything dynamically right now when you are used to delaying all that processing to partition activation.

Making changes to profiles is blazing fast because they are not actually changing any real resources, but you will pay the price during activation of that profile.  On the contrary, when you make a change to a running partition with a dynamic HMC change, all that processing that happens in the hypervisor and O/S to add that resource will happen immediately -- while you wait.  That’s right, while you wait means, well... you will be waiting.

I’ve actually done some benchmarks on new system setups to compare dynamic operations with HMC commands (chhwres - equivalent to the Enhanced HMC GUI)  to HMC profile change commands (chsyscfg commands) that get applied via the “chsyscfg -o apply” command.  The chhwres commands on either a running or inactive partition, tend to be slow to operate, while the equivalent profile changes are very fast until they are either applied via apply command or profile activation.  In the end, it comes down to when you are going to wait.  You can wait now, or you can wait later, but you are always going to wait for the actual resource creation in the hypervisor.

To be completely honest, I’m a command line guy.  Sure, I’ll use the HMC GUI to create small test partitions and add a few virtual network or virtual fiber channel connections when I must.  I’m much more likely to create a command script to do it all for anything more than a couple resources.  I don’t have the patience to create hundreds of virtual fiber channel connections on a giant Power 1080 one by one in a GUI.  That said, most IBM i admins don’t create a lot of resources except during hardware refreshes and migrations, so using the GUI is right way to learn – it’s also safer.

I’ll post some more details of the command line way of creating and configuring partitions and partition resources in the future for those that are interested in that approach.

Need Help?

If you need help fixing a profile problem, or with a hardware refresh or migration and don’t want to go it alone, the IBM i Technology Services team (formerly known as Lab Services) is available to help with implementation planning, execution, and knowledge transfer.  See for contact information or speak to your IBM Sales Representative or Business Partner.  If you are planning a new hardware purchase, you can include implementation services by the Technology Services team in your purchase.


I am an employee of IBM on the IBM i Technology Services team (formerly known as Lab Services).  The opinions in this post are my own and don't necessarily represent IBM's positions, strategies, or opinions.






Synchronize Current Configuration and configuration change on inactive partition in HMC Enhanced UI


Bart’s Blog - Enable classic HMC GUI on release V9R1


IBM Support - Saving Configuration Changes To Profile


How to create Shared Ethernet Adapater without touching VIOS


HMC – Enhanced+ interface tricks


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