Reserved Instance Utilization

I. Formal Definition

The percentage of an organisation's reserved instance commitment that is being applied against eligible compute usage in the current period. RI utilization differs from RI flexibility: utilization measures whether the reservation is being used at all, while flexibility measures the ability to apply across instance families and sizes. The federation requires RI utilization to be reported daily for every active reservation, with utilization below ninety-five percent over a fourteen-day window flagged for review under UFMS-001:2.4(d). Modification options are tracked in the reservation register.

II. Etymology

A coinage of the AWS Reserved Instance era from 2009 onwards; the metric was generalised across cloud providers offering analogous reservation instruments.

III. Federation Usage

Federation members publish RI utilization daily across all active reservations. Underutilization triggers reservation modification or sale in supported markets. The RI marketplace activity is reported under MEV-Annex:3.2 with proceeds reconciled.

IV. Related Terms

• ri-flexibility
• reserved-instance
• commitment-utilization
• unused-commitment

V. Authoritative Citations

• UFMS-001:2.4UFMS Article II - RI Utilization
• MEV-Annex:3.2MEV Annex III - RI Reporting

VI. Citation in BibTeX

@misc{ifo4_glossary_ri_utilization,
  title        = {{Reserved Instance Utilization}},
  author       = {{IFO4 Federation Editorial Board}},
  howpublished = {{IFO4 Federation Glossary, slug \texttt{ri-utilization}}},
  year         = {2026},
  url          = {https://ifo4.org/glossary/ri-utilization},
  note         = {Category: FinOps; key: ReservedInstanceUtilization}
}

VII. Challenge This Definition

Federation members and accredited practitioners may challenge any entry under TGS-002:1.7. Filed challenges are routed to the editorial board, triaged into the revision register, and resolved in writing on the public docket. The slug remains stable through any revision.