Glossary

Monitoring

Monitoring is the practice of collecting predefined signals from a system and alerting when they leave their expected ranges.

Short answer

What is monitoring?

Monitoring is the practice of collecting predefined signals from a system and alerting when they leave their expected ranges.

Explained two ways

Plain and technical

In plain terms

Monitoring means watching the numbers you decided matter (error rates, response times, memory usage), and being told when one of them looks wrong.

Technically

Monitoring covers known failure modes: signals are chosen in advance, thresholds or baselines are established, and evaluation runs continuously. Its limitation is that it can only detect conditions someone anticipated. Baseline-relative alerting, which compares a metric against its own historical behaviour including seasonality, generally outperforms static thresholds because a single number cannot be correct for both a weekday peak and a weekend trough.

Example

What it looks like in practice

A service error rate is compared against its own behaviour for this hour on this day of the week. It rises to four times normal for a Tuesday morning, and the responsible team is paged with the recent deployments already attached.
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