The Basics of Sub-Capacity PVU Licensing for IBM Software

A processor value unit (PVU) is a unit of measurement that IBM uses to determine licensing costs based on the kinds of processors deployed on servers where IBM software is installed. A server’s PVU count is defined by the brand, model and number of physical processors running in the server and the number of core chips per processor. In order to calculate the number of PVUs, it also is necessary to refer to IBM’s PVU-per-core ratings for current processor technologies, which are updated on IBM’s website here.

A sample, full-capacity, PVU-licensing calculation for IBM WebSphere MQ software on a hypothetical server is as follows:

Server stats:
Server/Processor: IBM 795-series POWER7
PVUs per core: 120 | Physical processors: 8 | Cores per processor: 4
PVU calculation: 120 PVUs/core x 8 processors/server x 4 cores/processor = 3,840 PVUs/server
Software price: $73.25/PVU (as of May 2011)
Licensing calculation: 3,840 PVUs/server x $73.25/PVU = $281,280.00/server

As an alternative, “sub-capacity” licensing gives IBM customers who use virtual-server technology the option to license IBM products based only on the PVUs made available to the licensed software, rather than on the total PVU count for that server (as in the example above). However, sub-capacity licensing also requires that IBM customers meet the following requirements:

  • Agree to IBM’s sub-capacity licensing terms. The most recent, form Sub-Capacity Licensing Attachment is available here.
  • Use eligible software products. The latest published statement by IBM on sub-capacity-eligible software is available here.
  • Use eligible virtualization technologies. The latest list of eligible, virtual-server technologies published by IBM is available here.
  • Use eligible processor technologies. The latest list of eligible processors published by IBM is available here.
  • Use the IBM License Metric Tool (ILMT). The ILMT is a software tool designed to assist with the maintenance of an inventory of PVU-based IBM software deployments. Sub-capacity users must use the ILMT on a regular basis to generate and retain inventory reports for audit purposes.

Returning to the above example, if the server in question is running an eligible virtualization technology to limit WebSphere MQ to 3 processors, the sub-capacity PVU-licensing calculation would be as follows:

PVU calculation: 120 PVUs/core x 3 processors/VM x 4 cores/processor = 1,440 PVUs/VM
Licensing calculation: 1,440 PVUs x $73.25/PVU = $105,480.00

Use of the sub-capacity licensing model therefore can result in significantly reduced licensing costs. Businesses with questions regarding whether it makes sense to license IBM software on a sub-capacity basis should consult with experienced licensing consultants.