Quick answer: Install uptime monitoring first, then add the layer that answers your most common failure question: logs for what happened, metrics for resource pressure, and error tracking for application exceptions.
Key Takeaways
- Logs explain events, metrics show trends, and error tracking groups application failures.
- Start with the signal that matches your most expensive failure mode.
- Avoid collecting data nobody reviews.
- Keep retention realistic for your budget and compliance needs.
Understand the three layers
Logs are detailed event records. They are useful when you need to know which request failed, which plugin threw an error, or which deployment changed behavior.
Metrics are numeric time series. CPU, memory, disk, response time, queue length, and database connections show whether the system is under pressure before it breaks.
- Use logs to investigate specific events.
- Use metrics to detect trends and capacity issues.
- Use error tracking to group recurring application exceptions.
Choose by failure mode
A WordPress content site often benefits from uptime, server metrics, and PHP error visibility before advanced tracing. A custom web app may need error tracking earlier because exceptions directly affect users.
The best first install is the one that would have shortened your last debugging session. If every issue starts with guessing, add the signal that removes the most guessing.
- Frequent 500 errors: add application error tracking.
- Slow pages under traffic: add server and database metrics.
- Mystery failures after changes: centralize logs.
- Unclear public availability: improve uptime checks first.
Control cost and noise
Observability tools can become expensive when every debug line, bot request, and low-value event is stored forever. Start with shorter retention and focused collection.
Noise also affects attention. A dashboard with twenty charts is less useful than three charts tied to actions: restart service, increase disk, rollback deploy, or investigate errors.
- Filter health check noise.
- Set retention by usefulness.
- Alert only on actionable signals.
- Document what each alert means.
Implementation Checklist
- Keep uptime monitoring as the base layer.
- Add logs, metrics, or errors based on recent incidents.
- Set data retention before costs grow.
- Review dashboards monthly and remove unused panels.
Frequently Asked Questions
Do small sites need observability?
They need a lightweight version: uptime checks, server health, backups, and a way to inspect errors. Complex tracing can wait.
What is the biggest observability mistake?
Collecting everything without deciding who reviews it, what triggers an alert, and what action follows.