The IBM i Cloud Just Got More Frictionless With Virtual Serial Numbers
January 31, 2022 Timothy Prickett Morgan
If the cloud is to be successful, it has to do more than provide a new deployment and pricing model for IT organizations. It has to also maintain and retain some of the important practices in use by the IT department. One of the big disconnections between on premises IBM equipment and capacity sold in the cloud has been the serial number that identifies a machine, which is a kind of birth certificate and Social Security number for each box that comes off the IBM factory lines.
That serial number is used to identify the machine for technical support purposes and, like a Vehicle Identification Number on a car, is used to identify the machine for ownership purposes, too. But perhaps more importantly, that serial number and the underlying configuration of the machine is used as a means of tying application and middleware – and its pricing – to a specific machine.
This latter practice was useful and completely fine for the many decades when companies deployed application software on top of a particular model of AS/400 – and usually on a single machine – with the OS/400 operating system and integrated database running atop the iron and supporting those applications. Each AS/400 model was given a software tier – generally related to the overall capacity of the machine, from the entry P05 class to the high-end P60 class – and third-party application providers generally used the same tiers to price their software.
When server virtualization broke onto the OS/400 scene with logical partitioning with OS/400 V4R4 in 1998, things started to fall apart. The physical machine still had a serial number, but the box could be carved up into LPARs, short for logical partitions and often called virtual machines, riding atop that physical machine, each with their own distinct OS/400 instance running on the server virtualization hypervisor, which was eventually allowed to support AIX and Linux and which was eventually transformed into the PowerVM that we know today.
The trouble is, there was no way to assign logical partitions a corresponding and immutable logical serial number, and thereby allow application software used in production to be pinned to a specific LPAR or set of LPARs corresponding to a smaller amount of capacity than the full machine and its assigned software tier. Lack of a virtual serial number has caused a tremendous amount of grief, with customers and ISVs bickering with each other about how much they should be paying for software licenses on their machines. Moreover, in a world of live migration of LPARs, which allows for a running LPAR to be moved from one physical machine to another, tying software licenses to a serial number was not just moot. (IBM calls live migration Live Partition Mobility, or LPM, just so you get the lingo straight. The rest of the world calls them VMs and the movement of them live migration.) It means that moving the software across machines would cause a mismatch in physical system serial numbers, and live migrating applications would stop them from running on the new machine.
And as has been talked about quietly for more than a year now, IBM is finally doing something to start fixing the issue by creating virtual serial numbers, which were unveiled on January 25 in announcement letter 122-017.
“Virtual Serial Numbers allows us to remove the dependency on the hardware and instead map the software to a virtual number, and that virtual number can move between hardware platforms,” explains Alison Butterill, IBM i offering manager at Big Blue. “We have a lot of service providers with workloads they need to move around. Today, the first instance of Virtual Serial Number is within the purview of an HMC. So within the systems that an HMC controls, it it’s under the purview of one HMC. Certainly we are looking at the next steps and definitely we are getting pressure from service providers to be able to move workloads around. So that’s definitely what we are looking at for the future. But today, if a service provider has an HMC controlling a couple of machines, then if the service provider has the licenses or owns the licenses themselves, they could definitely be moving those VSNs around under the purview of one HMC.”
The VSNs are not set up in IBM’s e-configurator system, but rather by customers after they receive and set up their Power Systems servers. VSNs are supported only for IBM i environments at the moment atop PowerVM, and only on entry “ZZ” Power S914, Power S922, and Power S924 machines using the Power9 processor, the high-end “Fleetwood” Power E980 announced in August 2018, and the Power10-based “Denali” Power E1080 system that launched last September. By the way, both the original Power9 entry machines – which have an “A” in their model name, such as 9009-41A for the Power S914 – that debuted in February 2018 – and those with enhanced PCI-Express 4.0 slots and enhanced flash memory that debuted in July 2020 – which have a “G” designation, such as the 9009-41G in the updated Power S914 – can have VSNs.
“We have a number of things that are being requested from our cloud providers,” Butterill continues. “The first item on their list was to remove that dependency on the physical serial number. So that’s what this announcement has done. It allows us to remove the dependency. But as you can imagine we have a long list of things that are begging requested. And certainly, more mobility is a request that we are getting in from service providers. Especially the applications. It is interesting because the applications are owned by the application vendors. Some of them have already taken steps to be more mobile in a cloud enticement by removing their dependency on a physical serial number or a partition name or whatever. Some of them have moved to a per user license. Some of them have moved to a per customer number license. But some of the ISVs have not done anything and we are hoping that this encourages them to, if needed, update their application and really take advantage of this virtual serial number.”
Virtual Serial Numbers are available as of January 25, and out of the gate IBM is offering them for machines in the IBM i P05, P10, P20, and P30 software tiers. (That covers all modern machines at any scale. There are no P40, P50, or P60 tier machines in the Power9 or Power10 lines.) The virtual serial numbers are available for no charge, as are virtual features for processor activations and core activations on the underlying Power9 and Power10 processors. It does cost $100 to enable each VSN, however, since IBM will have to keep track and authenticate these for its own software as well as those for ISVs.
We presume there is no arbitrary limit on the number of VSNs per machine and that it matches the maximum number of allowed LPARs on each machine.
In general, you can scale to 20 LPARs per CPU socket, but there is a limit of 1,000 LPARs on the Power E980 and Power E1080. We are not sure why this is the case, because in theory a Power E980 should be able to handle 3,840 LPARs and a Power E1080 should be able to handle 4,800 LPARs at 20 per core.
By the way, IBM has been talking about assigning VSNs for a while, not to just me and Alex on announcement calls, but to the tech community at large running Linux on Power, as you will see from the Related Resources section below. The talk last year was that it would only be formally activated on Power10 machines, and people were pretty annoyed it was not going to be on Power9 machines, so IBM has fixed that, too.
One more thing: On February 17 at 10 a.m. Eastern, Brandon Pederson, the IBM i product marketing manager, will host a webcast that covers VSNs as well as the New Navigator for i. IBM i product managers Dan Sundt and Linda Hirsch will be on the webcast as well as Tim Rowe, who is IBM i business architect of application development. You can register at this link.
One last thing: This VSN announcement does not say how IBM will be able to track the performance capacity of LPARs, which is how application software is often priced. But at least now there is a way to uniquely and immutably track a virtual machine as it lives on a physical machine and is transported around a network of machines and perhaps out to a cloud. What we need next is a virtual software tier, based on CPW capacity, and some means of locking that down – again, immutably – for software vendors that need a static software tier, or some means of metering average CPW capacity use so ISVs can come up with a monthly bill for software.
You can see why a lot of ISVs might just want to move to per-user pricing and be done with it all.
RELATED RESOURCES
Assigning The Virtual Serial Number To A Logical Partition, August 10, 2021
New Function: Virtual Serial Number, April 9, 2021
