Field notes

Reading uptime gaps across a family of internal apps

March 11, 2026 · Min-jun Park

Printed analytical charts spread across a wooden desk

When an internal payroll app misses its morning window, the ticket usually names that app alone. The same morning, inventory and leave-request systems may have slowed for twenty minutes without anyone filing a report. Stack health work starts by lining those clocks up.

Collect the last ninety days of availability notes from each business application, even the informal ones kept in chat threads. Align them on a shared timeline. Clusters that appear within the same fifteen-minute band often point to a shared database pool, authentication service, or batch job rather than separate application bugs.

In Busan offices we still see teams treat each ticket as a local defect. Crossing the timeline once usually reveals two or three shared choke points that explain a surprising share of the noise. Fix those first; the remaining tickets become easier to triage.

A practical next step: ask each application owner for their last ten user-visible incidents, with start and end times only. Skip root-cause essays until the cluster map exists. The map decides which essays are worth writing.

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