Migrating to AIX 7.3

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Follow this procedure to migrate to AIX® 7.3.

Notes:
  1. The boot logical volume requires 40 MB of contiguous disk space. During migrations, the inuextendblv command runs to ensure that there are contiguous partitions for hd5. If contiguous partitions are not present, the inuextendblv command attempts to create them. If the partitions are not present and the inuextendblv command fails to create them, the migration is stopped.
  2. The settings in your bootlist are not migrated. After a migration, the bootlist is set to the primary boot device.
Attention: This procedure requires shutting down and reinstalling the base operating system. Whenever you reinstall any operating system, schedule your downtime when it least impacts your workload to protect yourself from a possible loss of data or functionality. Before you perform a migration installation, ensure that you have reliable backups of your data and any customized applications or volume groups. For instructions on how to create a system backup, refer to Creating system backups.
When you migrate to a newer version of the AIX operating system, know that the default value of the j2_inodeCacheSize tunable parameter was changed from 400 to 200. The j2_inodeCacheSize tunable parameter allows approximately 50,000 open files per gigabyte (GB) of main memory, and improves system performance. However, the j2_inodeCacheSize tunable parameter value of 200 can cause issues in systems that have a small amount of main memory (4 GB or less) and many concurrent users or many concurrent open files. To fix these issues, you can change the values for the j2_inodeCacheSize and the j2_metadataCacheSize tunable parameters from 200 to the previous value of 400 by running the following command:
Note: When you run the following command, the current value and boot value of both the tunable parameters are reset.
ioo -p -o j2_inodeCacheSize=400 -o j2_metadataCacheSize=400

If the issues are not fixed after you change the values for the j2_inodeCacheSize and the j2_metadataCacheSize tunable parameters, you can contact IBM Support.

Prerequisites

Before starting the migration, complete the following prerequisites:

  • All requisite hardware, including any external devices (such as tape, CD, or DVD-ROM drives), must be physically connected. If you need further information, refer to the hardware documentation that accompanied your system.
  • Before migrating your BOS to AIX 7.3, ensure that the root user has a primary authentication method of SYSTEM. You can check this condition by typing the following command: 
    # lsuser -a auth1 root

    Change the value, if needed, by typing the following command:

    # chuser auth1=SYSTEM root
  • Before you begin the installation, other users who have access to your system must be logged off.
  • Verify that your applications run on AIX 7.3. Also, verify that your applications are binary-compatible with AIX 7.3. If your system is an application server, verify that there are no licensing issues. Refer to your application documentation or provider to verify on which levels of AIX your applications are supported and licensed.
  • Verify that your hardware microcode is up-to-date.
  • All requisite hardware, including any external devices (such as tape, CD, or DVD-ROM drives), must be physically connected and powered on. If you need further information, refer to the hardware documentation that accompanied your system.
  • Use the errpt command to generate an error report from entries in the system error log. To display a complete detailed report, type the following: 
    # errpt -a
  • Adequate disk space and memory must be available. You need at least 4 GB of memory a minimum of 20 GB of physical disk space. See the Disk Requirements topic in the Release Notes, and compare these requirements to the disk usage of the AIX Version 7.2 system.

    If new file systems are listed for AIX 7.3 that are not on the AIX Version 7.2 system, these file systems are created during migration. Ensure that the appropriate disk space is available before you begin the migration installation. Migration also takes more disk space for software installations than an overwrite installation.

  • Run the pre_migration script.
  • Make a backup copy of your system software and data. For instructions, see Creating system backups.
Note: For more information on the supported hardware with AIX 7.3, refer to the Release Notes.
To verify the processor capability, run the following command:
/usr/sbin/prtconf -c
The command returns CPU Type: 32-bit or CPU Type: 64-bit depending on the system capability. If your system does not have the prtconf command, you can use the bootinfo -y command.