MTTRllä

MTTRllä is a term used in some reliability engineering and IT operations discussions to describe a holistic extension of the standard metric mean time to repair (MTTR). Proponents view MTTRllä as both a metric and a framework that captures not only repair time but also the broader sequence of activities involved in restoring service, including preparation, detection, triage, repair, verification, and post-incident hardening.

Etymology and usage notes: The form MTTRllä combines MTTR with the Finnish instrumental suffix -llä, meaning “with” or “by,” reflecting a practice-oriented emphasis seen in some Nordic practitioner circles. It is not an official standard and its exact meaning can vary by organization or community.

Definition and measurement: In practice, MTTRllä is treated as a composite metric. There is no single universal formula. Common approaches break MTTRllä into phases such as mean time to detect (MTTD), mean time to diagnose/triage, mean time to repair, and time for verification and post-recovery hardening. Some describe MTTRlle as the sum or a weighted combination of these components, while others present it as a set of related metrics tracked together to reveal bottlenecks.

Calculation example: If an incident sequence has MTTD = 6 minutes, diagnostic/triage = 8 minutes, repair = 20 minutes, and verification/post-hardening = 6 minutes, MTTRlle could be reported as a total around 40 minutes (averaged across incidents) or as separate phase metrics to show where improvements are needed.

Applications and limitations: MTTRlle is used in IT service management, site reliability engineering, and manufacturing maintenance to emphasize end-to-end incident handling. Its lack of a universal formula can hinder comparability, and careful data collection is required to avoid double counting or misinterpretation.

See also: MTTR, MTBF, availability, incident management.