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Rob Batters Director of Managed & Technical Services




Author: Rob Batters
Director of Managed & Technical Services

As you might imagine, the use of IBM’s wide range of software comes with some very specific terms of use which, in turn, require that you are able to demonstrate compliance typically according to some form of metric. In this article, I’ll concentrate on one such measure, the “Processor Value Unit”, also known as the PVU.

The PVU exists because not all computers are created equal. I use many different computers in my line of work. Amongst these are a two processor laptop and a twenty four processor database engine. I could, if I were of a mind, deploy the same software to both machines. Given the disparity in their relative capabilities, it is not unreasonable to charge differently for the software on these two, very different systems. It’s also true that processors come in many different sizes. Some are capable of far more than others. Hence the PVU-based licensing model.

In practice, IBM place a value on each processor in a system depending upon the technology and its capability and represent that as the PVU for that type of processor. IBM defines a processor, for the purpose of PVU-based licensing, to be each processor core on a chip (socket). A dual-core processor chip, for example, has two processor cores. IBM publish their PVU values here:

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A long extant technology now, virtualisation delivers the ability to divide our computing technology into smaller units of usable resource bringing the benefits of dynamic scaling, reduced footprint, lower power consumption and many other others. However, installing software into a virtualised environment brings with it another challenge. The default position, of licensing the Full-Capacity of a system, makes little sense If, for example, all I want to do is to deploy my IBM software to a Virtual Machine occupying just 2 cores out of, say, a total of 16. How do I licence that correctly and avoid unnecessary charges? If I were to scale up the number of processors available to a VM, does my licence allow me to do that?

IBM permit such an arrangement through the use of a Sub-Capacity licensing agreement. Signatures to the agreement may, subject to a few other conditions, deploy software in line with the number of purchased PVUs. The question then is, how do you demonstrate compliance?

The IBM License Metric Tool (ILMT) helps you maintain an inventory of the PVU based software deployed for your Full Capacity or Virtualization Sub-Capacity environment, and measures the PVU licenses required by software product. It is intended to help you manage your IBM software licensing requirements, and help you achieve audit readiness. ILMT is available from IBM at no charge and our experienced consultants can help you advise, implement and manage it.