AIX system migration installation


System migration is a method of installing a system at a different version that is different from its current version. The IBM AIX installation provides various methods to install a system at different versions. You can choose the following methods:

  • A new and complete overwrite installation overwrites all data on the selected hard disk.
  • A preservative installation preserves old user data, which is in the root volume group.
  • A migration installation upgrades AIX to a different version or release while preserving the root volume group.

This article focuses on the AIX system migration installation method. It provides step-by-step instructions for migrating a system from one AIX version to another AIX version using a Network Installation Management (NIM) server.


A migration installation attempts to preserve all user configurations, while moving the operating system from one AIX version to another AIX version. During a migration installation, the installation process determines which optional software products are installed on the existing version of the operating system. The main advantage with the migration installation compared to a new and complete overwrite is that most of the file sets and data is preserved on the system. It keeps all the directories such as /home, /usr, /var, logical volumes information and configuration files. The /tmp file system is not preserved during the migration of the system.

During the migration of a system from one version to another AIX version, the following steps are taken:

  1. Saving the existing configuration files
  2. Preparinge and removing old files
  3. Restoring the system with new configuration files
  4. Removing unsupported or unnecessary file sets
  5. Migrating configuration data wherever it is applicable and possible
  6. Updating additional file sets when required by other file sets

The migration planning process involves various steps. The administrator has to prepare a checklist before migrating the system from one version to another AIX version to take care of the following steps:

  1. Backing up the current existing environment to prevent data loss
  2. Checking for the hardware requirements for the migrated version
  3. Checking for security vulnerability issues with the new AIX version
  4. Deciding on the migration strategy

Hardware requirements

Hardware requirements vary from one AIX version to another AIX version. Make sure that the new operating system supports your hardware. Read the release notes for your hardware and the corresponding AIX operating system requirements.

Also, along with checking the hardware, another important task to do on your system before starting a migration installation is to upgrade the microcode level of your system and of all adapters and other devices. Visit Fix central to find and download microcode upgrades, see the Related topics section.

Migration methods

There are different ways to migrate your system from one AIX version to another AIX version:

  • Migration by using NIM
  • Migration by using a CD or DVD drive
  • Migration by using mksysb
  • Migration by using a alternate disk migration.

These methods help to migrate the system from one version to another version. However, there are some advantages and disadvantages with these mechanisms.

If you have several systems in your environment, choosing the NIM method is the best option to migrate the system. The NIM method provides a mechanism to access the system remotely and it is the most time-saving method.

Note that the NIM master needs to be configured so that NIM clients can use the resource on the NIM master during the migration. Refer to the Resources section for configuring the NIM master.

Steps for migration using NIM

  1. Remove the /etc/niminfo file on the NIM client system if it exists.
  2. Run the smit nim command on the NIM client.
  3. Select Configure Network Installation Management Client Fileset for allocating the resource from the NIM master as show in Figure 1.
    Figure 1. smit nim
    NIM installation menu
    NIM installation menu
  4. Enter the system name as the host name of the NIM client that you want to install. In this example, P7he42 is shown as the NIM client. Enter the Primary Network Install Interface of the system as en0. Finally provide the NIM master details.

    Enter the host name of the network installation master from where you want to select lpp_source and location (for example, as shown in Figure 2.

    Figure 2. Providing the NIM master details on the NIM client
    NIM installation menu
    NIM installation menu
  5. Press Enter to continue. The command status is OK.
  6. Run the smit nim command again on the NIM client and select Manage Network Install Resource Allocation from the menu list and then select Allocate Network Install Resources as shown in Figure 3.
    Figure 3. Allocating resources on the NIM master
    NIM installation menu
    NIM installation menu
  7. Select the lpp_source and spot of the corresponding build which needs to be installed and press ENTER as shown in Figure 4. Resources will be allocated to the NIM client during this operation.
    Figure 4. Select NIM resources
    select the build
    select the build
  8. Run the smit nim command again and select Perform a NIM Client Operation from the menu list as shown in Figure 5.
    Figure 5. Perform NIM operation
    NIM Client operation
    NIM Client operation
  9. Select the bos_inst method for the NIM client installation as shown in Figure 6.
    Figure 6. bos_inst method of NIM client installation
    NIM Client operation
    NIM Client operation

    If your environment has automation scripts for the bos_inst installation, then select the prompt installation option during the resource allocation of the bos_inst script.

  10. Finally change the ACCEPT new license agreements value to Yes as shown in Figure 7 and press Enter to confirm the installation.
    Figure 7. Accepting new license
    Accepting new license
    Accepting new license
  11. After the NIM client operation, the client partition restarts automatically. Open a new terminal session using the Hardware Mangement Console (HMC). The client partition boots into the SMS menu and the resource allocation packet count starts to perform the OS installation.
    Figure 8. Select the terminal as system console
    SMS menu
    SMS menu

    After everything is successfully allocated, you are prompted to choose the system console as the opened terminal by selecting option 1 as shown in the above Figure 8. The installation options is displayed on this console.

  12. The installation options are displayed in English by selecting the option 1 as shown in the Figure 9.
    Figure 9. Displaying installation options in English
    Settings for installation
    Settings for installation
  13. Installation options are displayed to choose the method of the OS installation. For a migration and preservation installation, select option 2 as shown in Figure 10 to change the default installation settings.
    Figure 10. Change the installation settings
    Change the installation settings
    Change the installation settings
  14. After choosing the change/show installation settings as shown in Figure 10, you are promted to select the installation method. Choose option 3 for the migration installation as shown in Figure 11.
    Figure 11. Choosing the migration installation
    Migration installation
    Migration installation
  15. Choose the disk drive where the operating system needs to be installed by selecting the corresponding sequence number as shown in Figure 12.
    Figure 12. Choose required the disk drive from the list
    Lists disk drives
    Lists disk drives
  16. Finally change the primary language as required, by selecting option 2. After selecting the primary language, press 0 to install the operating system with the required installation settings as shown in Figure 13.
    Figure 13. Selection of language and installation settings
    Language settings
    Language settings

    The installation will proceed with the above settings. After the system is completely migrated to the targeted AIX version, the system automatically restarts. You can log in directly using Telnet or Secure Sheell (SSH) services.


A migration installation migrates a system from one AIX version to another AIX version. A migration installation preserves old user data and configuration files. The NIM installation method helps to migrate the system from one AIX version to another AIX version.

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Zone=AIX and UNIX, Open source
ArticleTitle=AIX system migration installation