Infrastructure · Verification
DetectorSelfTest
Test the detectors that guard a process, so their silence is not mistaken for health
Definition
Mechanism
On a stated schedule, known faults are injected or replayed, and each Monitor or check that guards a process is confirmed to catch them. A detector that misses a known fault is marked failed and repaired before the process relies on it again.
Invariants
- Each detector is tested with a known fault on a stated schedule.
- A detector that misses a known fault is marked failed and is not relied on until it is repaired.
Risks
Failure modes
Silent monitor
a detector stops firing and its silence is read as health.
Test-only detection
detectors catch the injected faults but not real ones.
Caution
Injected or replayed faults can fire the real responses their detectors drive — keep test faults tagged and isolated from live state.
Relationships
Builds on
References
Continuous observation of state over time
Used by
References
Check that a conserved quantity balances over every holder, as an equality, not as a lower bound on the holders being watched
Mind
When a value's meaning changes, find and recheck every reader of the old meaning