The Manufacturing Default Configuration (MDC) mode is the initial single partition setup provided with a new system, allowing it to function as a nonpartitioned server without requiring a Hardware Management Console (HMC). In this state, all physical resources are automatically assigned to the single logical partition, and any newly added hardware is also allocated to it, requiring only a dynamic update or restart to be usable.

Even in environments that intend to remain in single partition mode, administrators may still connect an HMC to take advantage of firmware updates, advanced system monitoring, or Capacity on Demand. Once partitions are created or modified through the HMC, the system transitions into partitioned mode and must be managed exclusively through the HMC. This makes MDC a simple baseline configuration that streamlines initial deployment while supporting future scalability. This blog explains the MDC mode, its characteristics, and how to transition an IBM i system from the HMC-managed logical partition (LPAR) mode to the MDC mode.

Prerequisites: Baseboard management controller (BMC) firmware level FW1060 or later is required for this procedure.

What is MDC mode?

MDC mode is a baseline configuration designed for systems that do not require partitioning.

• It is the baseline configuration included with the system.
• It runs as a single partition, with all available resources (CPU, memory, and I/O) assigned to it.

Convert an IBM i system from HMC-managed LPAR mode to MDC mode

Use the following steps to convert an IBM i system from the HMC-managed LPAR mode to the MDC mode when a single-partition configuration is required.

1. Ensure that the system is connected to the HMC.
   
   
2. Note down the physical location code for Load source and Alternate restart device from the HMC partition profile.
   
   
3. Back up the server profile in the HMC for future use.
   
   
4. Create a new profile for the local area network (LAN) console (select the same load source and alternate restart device and set the console tag to an operational communication card).
   
   
5. In IBM i Access Client Solutions, open the system configuration, edit the selected system and go to the Console tab, and change the console type from HMC 5250 Console to LAN Console.
   
   
6. Activate the IBM i partition with the new profile. Wait until SRC C60041F6 or C6004036 appears in the HMC GUI; then start the Access Client Solutions session with the new LAN console connection.
   
   
7. Power off the partition and the server.
8. Start the Power Hypervisor in the standby mode.
   
   
9. Initialize the server from the HMC interface by navigating to the appropriate configuration option.
   
   
   
10. Sign in to the HMC command line and run the lpcfgop -m managed_system_name -o clear command. Replace managed_system_name with the actual system name.
    

    Note: The server is now in the MDC mode but is still managed by the HMC.

    
11. Power off the server. In the HMC GUI, remove the connection to the server.
    

    Note: From the baseboard management controller (BMC), use the Advanced System Management Interface (ASMI) and verify that no HMCs are attached.

    Click Security and access > HMC and user sessions.

    
12. Then, perform a factory reset from ASMI:
    Click Settings > Factory reset. Select Reset server settings only and click Reset.
    
    
13. The ASMI interface provides an option to reinstall the partition in D (Boot from media / drives) mode. This step helps ensure that the system uses the same physical location codes for the load source and the alternate restart device that were noted down earlier in step 2. To reinstall:
    
    1. In the ASMI window, set the boot mode to D (Boot from media / drives).
    2. Enter the location codes for the load source and the alternate restart device noted in step 2.
    3. Confirm that the IBM i console is correctly set to the operational communication card.
    4. Power on the server.
    5. Proceed with reinstalling the partition using these devices.
       
       

MDC mode versus HMC-managed LPAR mode

The following comparison highlights the key differences between MDC mode and HMC-managed LPAR mode to help determine the appropriate configuration for a given environment.

Licensing considerations in the MDC mode

When using MDC mode, it is important to understand how system resource allocation affects IBM i licensing.

One common challenge with MDC mode is IBM i licensing tied to processor cores. For example, a customer may have purchased IBM i licenses for only one core, but the server hardware includes four cores. In MDC mode, the single partition uses all available cores by default, which can exceed the licensed entitlement.

To remain compliant, administrators may need to use techniques such as field core override to reduce the number of functional cores assigned to the partition. This ensures that the system operates within the licensed limits while still benefiting from the simplicity of MDC mode.

Key takeaways

Consider the following key points when working with MDC mode:

• MDC mode can be a permanent production solution for users who want a system with only one partition.
• Transitioning to managed partition mode is essential to leverage the full capabilities of the server with IBM i.

Conclusion

IBM i in MDC mode is like the training wheels on a new bike; it helps administrators get started safely, but the real power comes when administrators move into managed LPAR configurations. By understanding MDC mode, administrators can better appreciate the journey from factory defaults to enterprise-grade virtualization. Understanding when to use MDC mode versus managed LPAR mode helps administrators make informed decisions based on their workload and scalability requirements.