Quarterly ILMT Reports and the Two Year Retention Requirement

Sub-capacity licensing can cut your IBM bill dramatically, but it comes with conditions. Two of the strictest are the quarterly ILMT report and the requirement to keep those reports for two years. Miss them, and IBM can charge your virtual estate as if every core were fully licensed.

The rule in plain terms

To license eligible IBM software at sub-capacity rather than full capacity, you must deploy the IBM License Metric Tool, keep it running continuously, generate processor value unit consumption reports at least once per quarter, and retain those reports for at least two years. These are not best practices. They are the conditions of eligibility. When they are not met, IBM is entitled to revert your position to full-capacity charging, which counts every physical core in the environment.

Why quarterly reports exist

Sub-capacity licensing lets you pay for the virtual capacity your software actually uses rather than the full physical capacity of the host. That is a meaningful saving, but it requires evidence. The quarterly report is that evidence: a point-in-time record of peak processor value unit consumption per product. Without a continuous series of these reports, there is no proof of what your virtual consumption was, and the auditor falls back to the worst case for you.

The two year retention requirement

Generating the report is only half the obligation. You must also keep it. The retention window is two years, which means at any audit you should be able to produce a continuous quarterly history covering the look-back period. A report that was generated but not retained is, for audit purposes, a report that never existed. Auditors routinely ask for the full back history, not just the current quarter, precisely because gaps in the record are where full-capacity findings are made.

What happens when reports are missing

• The affected products lose sub-capacity eligibility for the periods that are not evidenced.
• Charging reverts to full capacity, counting every physical core in the cluster or host.
• A modest virtual footprint can be reassessed against a much larger physical one.
• The gap becomes a finding that is difficult to challenge without the historical data.

The financial swing between sub-capacity and full-capacity charging is often the single largest line in an IBM audit. Retention discipline is what protects it.

Building a retention discipline

The fix is procedural, not technical. Schedule the report generation so it cannot be skipped, store the output where it will survive server rebuilds and staff turnover, and verify quarterly that the series is unbroken. Treat the two year window as a rolling archive, not a one-time export. Where history is already incomplete, the priority is to reconstruct what can be defended and to correct the configuration before the next report is due.