Expanding The Operating System Matrix For Power10
November 1, 2021 Timothy Prickett Morgan
As enterprise platforms go, the Power Systems family of machines has had an expansive operating system support matrix. One of the reasons why the Power line has persisted – and its rivals at Hewlett Packard Enterprise and Sun Microsystems did not – is that not only did IBM keep making enhancements to its proprietary AIX and OS/400/IBM i platforms, but two decades ago formally adopted SUSE Linux Enterprise Server and Red Hat Enterprise Linux as alternative platforms.
With the launch of the “Cirrus” Power10 processors in the enterprise-class “Denali” Power E1080 in early September, IBM continued its long practice of have multiple releases of these four operating systems available concurrently on the Power10 machines. Presumably, what is true of the high-end Power E1080 will be true of the entry and midrange Power10 machines coming next year, probably around May or June if all goes as planned. But we think that the support matrix is not generous enough for IBM i customers and is not as generous as what IBM is doing for AIX. In fact, we think that IBM could do – and should do – a wider support matrix to get customers who are, for whatever reason, trapped on prior IBM i and AIX versions and releases able to move to Power10 iron.
Before we get into that, let’s talk about the actual operating system support matrix for Power10 iron, which was given to business partners concurrently with the Power E1080 rollout. Take a look at this and then we can talk about it:
This chart comes with two important caveats. The first is familiar to everyone in the IBM midrange: “All statements regarding IBM’s future direction and intent are subject to change or withdrawal without notice and represent goals and objectives only.” IBM also reminds everyone that for many years to come, as new software versions and releases are made available for IBM i, AIX, RHEL, and SLES, they will of course be supported on Power10 processors. And if history is any guide, this will be the case when Power11 chips are in the field in 2024 or 2025 and until Power12 chips are available in 2027 or 2028. Roughly speaking.
What sticks out most in the chart above, to our eyes, is that future RHEL 8.4 and RHEL 9 releases are scheduled for both Power9 and Power10 processors in the second quarter of 2022, which we think probably means that they are coincident with the entry and midrange Power10 launch.
The other thing that sticks out is that AIX support is broader than for IBM i, which seems unfair if you think about the fact that there maybe three to five times as many IBM i customers as there are AIX customers. (I think there are 120,000 IBM i shops and maybe 30,000 AIX shops in the world.) AIX 7.1 at Technology Level 5 with Service Pack 4 can run on Power10 iron in Power8 mode (meaning some of the features of the Power9 and Power10 chips, like their vector and matrix math units or special instructions, are not supported) in conjunction with the Virtual I/O Server. AIX 7.2 TL5 SP1 and TL4 SP1 are both supported on Power10, but only in Power9 mode.
This is a lot more than IBM i shops are getting for their IBM i 7.1 and IBM i 7.2 releases, which are roughly of the same vintage as AIX 7.1 and AIX 7.2. I don’t like those charcoal-colored boxes that show “Not Supported” for IBM i 7.1 and IBM i 7.2 releases on Power10 chips. Simply put, we need more legacy support for IBM i. We don’t just need parity, but we need to go back further because so much of the IBM i installed base is on IBM i 7.2 or earlier releases. We think there is plenty of V6.1 and even some V5R4 and even V5R3 out there in the installed base, and we think that surveys such as the annual IBM i Marketplace Survey report give us a good sense of what is going on among the IBM i shops that tend to stay current and who tend to buy tools and respond to surveys, but it undercounts and underrepresents the broader – and older – base of machinery.
At the very least, as Big Blue has done with IBM i 7.1 and IBM i 7.2 support on Power9 chips, which run atop the Virtual I/O Server (which virtualizes network and I/O), it seems like a good idea – despite the extra cost and extra hassle that IBM has to deal with – to get these earlier releases supported in some mode – and certainly not native Power10 mode but possibly in Power9 or even Power8 mode – on the Power10 processors. Yes, there will be plenty of older Power Systems iron available in the market next year when the Power10 machines go in, so Big Blue could rebadge and resell older Power8 and Power9 machinery to support these old releases. But we think this is short-sighted and that IBM should try to come up with a plan to get a larger portion of the IBM i installed base to move ahead to Power10 iron, and to do so even with an older IBM i release that is crimped in some way to make older software run on shiny new iron.
Customers will have lots more performance per core with Power10 chips than they had with Power9 chips, and certainly with Power8, Power7+, and Power7 chips. So some of that extra performance that can be had from the move can be used to support virtualized instances of the prior IBM i releases. I personally don’t care if they triple nest the hypervisors and operating systems to make this work. Burn the clock cycles. Put PowerVM on a Power10 machine, and then run another PowerVM layer that thinks it is in Power9 mode on top of that, and load up a partition within that and keep nesting until you have an OS/400 V5R3 or OS/400 V5R4 running
Getting older OS/400 and IBM i releases to run on new iron is more important than anything, and that is because from here customers can either keep using application software they know and love. (Or, at least know if they don’t love it.) It is the application software that matters, which should be obvious to any IBMer that is familiar with the mandate for the follow-ons to the original IBM Application System/400. Ease of application development and long term application support are the hallmarks of the AS/400 and IBM i platform. So the operating system support has to reflect that better. No complaints about budgets. No complaints about the complexity IBM has to deal with. That’s IBM’s job, and it is one of the reasons why IBM i shops are paying a considerable premium in the first place for the Power Systems iron and operating systems.