Preparing for Your POWER 11 Migration

IBM Champion Jaqui Lynch reviews the housekeeping that must be done before you migrate your systems to POWER11

Jaqui Lynch September 18, 2025

In July 2025, IBM released AIX the V7.3.3.1, HMC V11 and PowerVM 4.1.1.10 updates along with the POWER 11 servers. Before you migrate to POWER 11, there is some housekeeping to do.

The two key items involve the HMC and POWER8 (and older) servers. POWER11 requires the HMC to run at V11, which does not support POWER8 servers. Since the 7063-CR1 HMC is a POWER8 server, you will need to either replace it with a 7063-CR2 or a supported virtual HMC. Additionally, if you still have POWER8 (or earlier) servers, they are not supported by V11 of the HMC code, so you may need to bring in the new HMC for your POWER9 and higher servers and keep the older HMC for those older servers until you can replace them.

HMC v11

To update to V11, you will need to download the recovery DVD (as this is a version change) and you should also check if the BMC and PNOR need updating. The recovery DVD and Network version can be downloaded from ESS. The BMC and PNOR are downloaded from Fix Central – select POWER and then scroll to the bottom to find the HMCs.

Once you have downloaded the code you can follow the instructions in the readme to upgrade the HMC (or install if this is a new HMC).

Minimum VIO Server Levels and Upgrade Notes

The minimum levels required for AIX, the VIO servers, Linux and IBM i are all listed in the product announcement letters as well as in the Technical Overview Redbook for the specific server. As an example, the levels listed for PowerVM for any of the POWER11 servers are:

VIOS 4.1.1.10 (Service Pack)

VIOS 4.1.0.40 (Service Pack) (P10 compatibility mode)

VIOS 3.1.4.60 (Service Pack) (P9 compatibility mode).

You should note that 4.1.0.40 goes end-of-service on Nov. 30, 2026, and 3.1.4.60 goes end-of-service on April 30, 2026, so the recommendation is to update to 4.1.1.10, which is supported until Dec. 31, 2027. Under the covers, 4.1.1.10 is basically AIX 7.3.3.1, which means your NIM server would need to be updated to AIX 7.3.3.1 to support restores and builds.

PowerVM 4.1.1.10 was released in July 2025 and includes support for Power11 as well as enhancements to viosupgrade, viosbr, VFC, NFS-mounted ISO images, LPM, updateios and many other areas. Details of these are in the PowerVM 4.1.1.10 Release Notes.

Existing VIOS systems with supported versions of 3.1.x.y can be upgraded to VIOS version 4.1.1.0 (DVD image) or 4.1.1.10 (Flash image) using the viosupgrade tool. If you are already on V4, you can download the fixpack from Fix Central and then use updateios to update the VIO to v4.1.1.10.

Minimum AIX Levels and Upgrade Notes

The minimum supported level of AIX depends on whether it is being run standalone or under a VIO server. There is a large list of what is supported in each case, and it varies by server.

Below is what is included in the Redbook for the S1122 and S1124:

If installing the AIX operating system LPAR with any I/O configuration (one of these):

AIX Version 7.3 with the 7300-03 Technology Level and Service Pack 7300-03-01-2520 or later
AIX Version 7.2 with the 7200-05 Technology Level and Service Pack 7200-05-10-2520 or later
AIX Version 7.3 with the 7300-02 Technology Level and Service Pack 7300-02-04-2520 or later (planned availability Aug. 8, 2025)

If installing the AIX operating system Virtual I/O-only LPAR (one of these):

AIX Version 7.3 with the 7300-03 Technology Level and Service Pack 7300-03-00-2446 or later
AIX Version 7.3 with the 7300-02 Technology Level and Service Pack 7300-02-02-2420 or later
AIX Version 7.2 with the 7200-05 Technology Level and Service Pack 7200-05-08-2420 or later

If installing IBM i:

IBM i 7.6 with Power11 GA PTF Group or later
IBM i 7.5 TR6 or later
IBM i 7.4 TR12 or later

You should also keep in mind the end of support dates, which you can find here:

HMC, AIX, IBM i, PowerVM . These are all linked, along with the Linux support, from the Flrtlite home page.

Power and Cooling

Another item you need to plan for is maximum power and cooling, along with rack space. Details of these are in the announcement letters and also in the Technical Overview Redbooks. Below is a summary, but you should also check the IBM documentation to be sure you are looking at the latest. I always plan for max kVAs, and this is explained in an article I wrote a while back.

E1180

Electrical power: up to 4.6 kVA per node

Wet bulb (caloric value): 15,355 kcal/hour or Btu

E1150

Thermal output (maximum): 7643 BTU/hr per system node

Maximum power consumption: 4950 W per system node

Maximum kVA⁴: 5.1 kVA per system node

S1122

Thermal output (maximum): 16.889 BTU/hr

Maximum power consumption³: 2240 W

Maximum kVA⁴: 2.31 kVA

S1124

Thermal output (maximum): 10065 BTU/hr

Maximum power consumption³: 2950 W

Maximum kVA⁴: 3.04 kVA

On Your Marks, Get Set …

It’s time to start preparing for your POWER11 upgrades. This involves getting your VIO servers and operating systems current, and replacing and preparing for any required HMC updates. This also means your systems will be current, supported and fully patched prior to integrating the new POWER11 servers.

Happy updating!