The three pillars of observability.
Logs, Metrics, Traces: the three pillars of observability
design for the day something breaks
Logs grow fast — sample or sample-by-route.
Logs are events, metrics are measurements, traces follow a request through services. You need all three; each answers different questions.
Logs: 'what happened' — searchable, structured.
Metrics: 'how often / how much' — cheap, time-series.
Traces: 'where time went in this request' — sampled.
Correlate via trace_id/span_id propagated through headers (W3C trace-context).
User reports 'sometimes slow'.