Monitoring
Measure availability, error rates, latency and anomalous behavior so that problems become visible early.
Reliability
Search must remain predictable, even when something goes wrong.
Reliability means not only rapid responses, but also visibility of errors, controlled changes and an appropriate fallback when a component is temporarily unavailable.
Fallback
Prevent a temporary search problem from rendering the entire storefront unusable.
Performance
Test under realistic load and pay attention to slow outliers in addition to averages.
Changes
Use acceptance, regression tests, and phased rollout for impactful adjustments.
Diagnosis
Error messages and logging must provide sufficient context to quickly investigate what happened.
Recoverability
Make clear how configuration or deployment changes are reversed when results deteriorate.