Db2 sub-capacity compliance under audit.

Db2 is licensed per Processor Value Unit, and sub-capacity rights are what stand between you and a full-capacity bill. Under audit those rights are not assumed. They are tested, and they are easy to lose on a technicality.

Why Db2 sub-capacity is a frequent target

Db2 runs on PVU, a core based metric. Without sub-capacity rights every physical core in a host or cluster where Db2 is installed is licensable, whether Db2 uses it or not. Sub-capacity licensing lets you license only the virtual cores actually allocated to the workload. The gap between the two numbers is large, which is exactly why auditors probe it first.

The catch is that sub-capacity is conditional. It depends on eligible virtualization technology and on the IBM License Metric Tool being deployed and operating correctly. When either condition fails, IBM is entitled to revert the count to full capacity, and the finding swells accordingly.

The four conditions an auditor checks

• ILMT was installed within 90 days of the first eligible Db2 deployment.
• ILMT has run continuously since, with no extended gaps in scan data.
• Quarterly sub-capacity reports were generated and retained for two years.
• The virtualization technology under Db2 is on the eligible list.

Miss any one and the auditor has grounds to charge full capacity for the affected period. The most common failure is not a missing tool but a tool that ran with stale data, lost VM manager connections, or miscategorized the Db2 bundle. The result reads as non-compliance even when the underlying deployment was modest.

Where the count goes wrong

Idle and allocated cores

On Power LPAR and similar platforms, allocated cores can count even when idle. If your sub-capacity report does not reflect the true entitled virtual core allocation, the auditor will read the higher physical figure. Reconcile what ILMT reported against what was actually allocated to Db2.

Bundled Db2 mistaken for full Db2

Db2 ships bundled inside other IBM products with a restricted use license. If ILMT classified a bundled instance as a standalone Db2 entitlement, it inflates your apparent deployment. That misclassification is correctable, and correcting it removes cores from the count.

How to defend the lower number

The defense is evidentiary, not rhetorical. Rebuild the sub-capacity position from your own scan history and entitlement records before you accept the auditor figure. Where ILMT coverage lapsed, document the remediation and the corrected counts so the full-capacity assumption applies, at most, to the genuine gap window and not to the whole estate.

Our method runs this as Contain, Reconcile, Challenge, Settle: contain the data IBM receives, reconcile the deployment independently, challenge each full-capacity assumption with evidence, and settle the residual down.