Below are some of our most frequently asked questions about Sub-capacity licensing. To view answers, simply click a question.

Sub-capacity FAQs: Overview Questions

# Question

Sub-capacity FAQs: Overview Answers

# Question Answer
1 What is sub-capacity (virtualization) licensing and how is it different from standard licensing?
Sub-capacity licensing lets you license a PVU-based software program for less than the full processor core capacity of the server, when the software program is deployed in an eligible virtualization environment. With full capacity licensing, customers are required to obtain PVU license entitlements for all activated processor cores in the server, regardless of how the software was deployed.
  • IBM’s Passport Advantage Sub-Capacity Licensing offering...
    enables customers to leverage server virtualization to more effectively consolidate their infrastructure and reduce their overall total cost of ownership (TCO)
  • allows flexible software licensing using advanced virtualization capabilities such as shared processor pools, micro-partitioning, virtual machines and dynamic reallocation of resources
  • gives growing customers the flexibility to choose how to add workload environments without making trade-offs between hardware design and software licensing
  • enables customers to license software for only the processor core capacity available to the partition hosting the IBM software
  • provides a tool (ILMT) which allows the customer to track and manage the processor core capacity available to IBM PVU-based middleware
2 What is virtualization licensing and how does it relate to sub-capacity licensing?
Recognizing that the use of the word “virtualization” has become commonplace in the industry, IBM will sometimes refer to its "Sub-capacity” offering as “Virtualization Capacity” or "Virtualization Licensing". You should expect these names to be used interchangeably for a period of time.
3 What is full capacity licensing and how does it relate to sub-capacity licensing?
Full capacity licensing is based on every physical, activated processor core in the physical server. Back when servers were one processor core sitting on top of one chip plugged into one socket, software was licensed on full capacity basis by default. The concept of full capacity licensing has not changed, even with the proliferation of multi-core and multi-socket servers. Licensing was basically simple. But with partitioning and more sophisticated server virtualization technologies that create virtual CPUs, virtual servers/partitions (aka virtual machines, LPARs, etc.) that can be moved and/or resized on the fly, came the demand for more flexible licensing terms. Thus IBM announced its sub-capacity licensing offering back in 2005. Today, IBM has the broadest support of virtualization technologies in the industry, including RISC and x86 platforms, and Linux on System z. In addition we are the only vendor which provides a tool to assist customers in maintaining compliance.
4 Is a tool currently required to track sub-capacity license use
Yes, the use of IBM License Metric Tool (or IBM BigFix Inventory) is now required for sub-capacity licensing.
5 Are customers required to report their license deployments to IBM?
Customers are no longer required to submit a report of their license deployments to IBM as a result of the November 6, 2007 announcement. Instead, customers must maintain documentation as evidence of on-going license compliance management of PVU capacity available to IBM middleware. As per the terms of the offering, customers must make these reports available upon IBM request (refer to the IBM Passport Advantage Agreement).
6 Does IBM require that customer's report their sub-capacity results each quarter similar to how SCRT is used for System z software?
No, see the previous question. SCRT (Sub-Capacity Reporting Tool) is only used in support of System z software. For more information on sub-capacity licensing for System z software visit the Sub-Capacity Corner
7 What are the differences between System z (mainframe) and distributed server sub-cap offerings?
SCRT is used for mainframes and SCRT requires periodic reporting to IBM.

ILMT is used for distributed server platforms, including Linux running in System z IFLs or engines.

Refer to Overview FAQ #5 for ILMT reporting requirements.

For more information on System z sub-capacity licensing refer to the Sub-Capacity Corner.

Additional information is available on the Sub-Capacity Licensing portion of the Passport Advantage Web.


8 Is sub-capacity licensing available for other server software products that are not licensed based on PVUs?
Select WAS and DB2 per Limited Use Socket and RVU Managed Core offerings are also eligible for sub-capacity licensing.
9 How can I determine if a product is licensed based on PVUs?
The product and/or part number description will almost always state the licensing metric. The following links are sources for Passport Advantage pricing/licensing:
- IBM License Information document database
- Passport Advantage Online:
- IBM Software Online Catalog (via
10 What is the algorithm for determining "sub-capacity pricing"?
IBM licenses on the basis of whole processor cores, based on the lower of the physical or the virtual cores. The minimum requirement for software licensing is the appropriate number of PVU license entitlements for one processor core. This licensing is based on the processing capacity (expressed in PVUs) available to the IBM middleware. IBM licenses to the lower of the sum of virtual capacity or the full (physical) capacity of the server. Reference the Virtualization Licensing Counting Rules for details and examples on calculating sub-capacity license requirements in various scenarios.
11 Can we license PVU entitlements for one processor core in a server, for all eligible virtualization environments?
Yes. Please refer to the list of eligible processor technologies(PDF, 17KB) and eligible virtualization technologies.(PDF, 40KB)
12 Can we license PVU entitlements for less then one processor core in a server, for all eligible virtualization environments?
No. The minimum requirement for software licensing is the appropriate number of PVU license entitlements for one whole processor core.
13 How many PVU license entitlements are required for a virtual machine (VM) in a VMware virtualization environment?
PVU licensing is based on the processing capacity (expressed in PVUs) available to the IBM middleware. In the case of VMware, we license based on the number of  virtual cores  (vCPUs in VMware terminology) available to a partition. Each vCPU is equal to one processor core for PVU licensing. We license to the lower of the sum of vCPUs or full (physical) capacity of the server.  For additional details, view Counting Software licenses using specific virtualization technologies.
14 How many PVU license entitlements are required for a partition in an eligible PowerVM virtualization environment?
PVU licensing is based on the processing capacity (expressed in PVUs) available to the IBM middleware. In the case of a PowerVM partition we license based on the virtual processor core capacity available to a partition depending on the partition mode (capped or uncapped).
In the case of a certain partitions (capped partitions) that have a fractional core processing capacity, we aggregate fractional processor cores, apply shared pool capping rules, and round up at the server level to the next whole processor core.
IBM licenses to the lower of the sum of virtual cores or the full (physical) capacity of the server
For additional details, find the scenario that best depicts your situation by going to:
Scenarios for Power Systems(PDF, 447KB) available from Counting Software licenses using specific virtualization technologies.
15 Why are some PVU-based products ineligible for sub-capacity licensing?
For those few exceptions, the products are typically not capable of being deployed in a virtualized server environment, the product is always deployed on the entire server environment, or the product solution's architecture is such that ILMT is unable to discover the processor core capacity of the virtualized server environment. These products must be licensed on a full capacity basis. See the Passport Advantage Sub-capacity Licensing Eligible Product Statement.(PDF, 24KB)
16 Are the Express and Workgroup products eligible for the sub-capacity offering?
Yes, as long as the PVU metric is available and used. Some Express products were made eligible for sub-capacity licensing early in 2009 prior to the April 7, 2009 announcement, and then the rest were added. The flexibility of sub-cap for Express products does not change the PVU and computing capacity restrictions described in the documents below:
Licensing Guidance(PDF, 195KB)
17 Are the per-socket pricing options announced in May 2009 for certain Information Management 'workgroup' products eligible for the sub-capacity offering?
Yes, those products currently are: DB2 Workgroup, IDS Workgroup, Informix Warehouse for Workgroup Edition, InfoSphere Warehouse Departmental, and InfoSphere Warehouse Departmental Base. While these specific Workgroup products can leverage sub-capacity licensing, it should be noted that currently the maximum physical size of the server workgroup runs on is 4 sockets. With Express you have to pay for one server per physical or virtual machine and it limits itself to just 4 cores and 4 GB of memory. You could use LPARs or other virtualization technology and just pay for the sockets you use. However the physical server size has to be less than 4 sockets -- this means you cannot partition up a huge Power Systems server (bigger than 4 sockets) and just purchase workgroup on smaller LPARs.
18 Where can I find FAQs specific to Processor Value Units? View or download the Processor Value Unit FAQ for customers(PDF, 32KB)
19 Are there extra charges associated with a license acquisition that leverage sub-capacity?
No, IBM is not charging any additional fees for the customer to acquire sub-capacity terms for eligible products. While IBM provides ILMT to customers for no-charge, customers are responsible for the underlying infrastructure (server, network, etc.) and resources to deploy and manage it. Most customers capable of deploying complex virtualized server technologies such as PowerVM and VMware, will have the capability of deploying ILMT.
20 Is sub-capacity licensing available for both Passport Advantage and Passport Advantage Express customers?
21 How will customers that already have full cap licenses acquire sub-cap licenses?
With the April 7, 2009 announcements, existing license entitlements that had previously been used for full capacity deployments, can be used for sub-capacity deployments.
22 How do customers enroll in the Sub-capacity Licensing program?
Effective July 18, 2011, customers no longer have to enroll separately for Sub-capacity licensing. Sub-capacity licensing terms are included in the IPAA. Visit Passport Advantage Online for more details.
23 If a customer has a 16 processor core server, but only 8 cores have been activated, is this sub-capacity?
No. Full capacity licensing requires the customer to only acquire PVUs for the 8 activated cores in this situation. As more processors are activated, the customer needs to acquire additional software license entitlements. Sub-capacity will only apply if the customer sets up partitions that have less than 8 active processor cores available. See the next FAQ below for more information on activated processor cores.
24 Are customers required to acquire license entitlements for deactivated processor cores on a server?
No. IBM only requires licenses for activated processor cores. Some servers, like IBM's System p and System i, may be delivered with one or more processor cores deactivated, or turned off, to allow for future system growth. For instance, a system may ship with 8 physical processor cores where only 6 have been activated. This would allow the customer to have the additional 2 processor cores turned on in the future as their workload requirements grow. For software that is licensed on a per core basis, this server only contains 6 activated processor cores. Clients would only be required to obtain software licenses for all activated processor cores available for use on the server, so in this example, licenses are not required for the remaining 2 cores until they are activated.
Another common example is a system that contains a dual-core chip where only 1 processor core is activated (this is possible for most RISC processor cores, such as POWER6, but not for x86 processor cores). Again, this is a common configuration for IBM's Power Systems servers. In this example, even though there are 2 physical cores on the chip, since only 1 processor core is activated, licenses are only required for this one processor core. For example, if this is a POWER6-based system, then 120 PVUs would be required for the one activated core.
Activated processor cores are physical processor cores that are available for use in a server. They include processor cores:
  • that are activated (available for use) when the server is shipped by the manufacturer
  • that are activated subsequently through activation codes purchased from the server manufacturer by the customer

In summary, additional licenses are required at the time any additional processor cores are activated.
25 How can a customer keep track of partition size changes if the customer is using dynamic LPARs or virtual partitions?
With some server virtualization technologies, a customer must intervene to increase the size of the partition, and the customer is required to track these changes and to acquire enough license entitlements to ensure compliance with the partition size adjustments. More sophisticated server virtualization technologies can automate the re-sizing and/or movement of partitions without manual intervention. For virtualization technologies supported by ILMT, the tool will assist the customer in tracking these changes and will record the high water mark reflecting the maximum (peak) capacity. In environments where manual tracking is used. Customers must rely on other documentation, system log, and/or control processes to ensure license compliance with partition size adjustments.
26 If mobility is employed in a virtual environment (e.g. Power Live Partition Mobility, XenMotion or Quick Migration), are virtual cores counted each time they move to a new server?
No. Virtual cores in a virtual machine (VM) that has moved as a result of a mobility event will not be counted more than once. The same VM may not run on two servers simultaneously.
27 What information is available to customers to learn more about ILMT and the Sub-Capacity licensing offering?
View or download the Sub-capacity licensing overview(PDF, 425KB)

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