Template
Keep a hypothesis–test–result ledger
Without notes, troubleshooting quietly turns into reruns and folklore.
When it fits
- A diagnosis spans many attempts, people or configuration changes.
When to avoid it
- The ledger is not a dumping ground for secrets, personal data or unverified blame.
A template to use
[time] Hypothesis: [hypothesis]. Test/change: [action]. Observed: [result]. Interpretation: [what this weakens or supports]. Rollback/state note: [state].
Why it matters
Record each active hypothesis, the test used, the observed result and what changed because of it. Also record deliberate system changes and how to undo them. Keep entries factual enough that a new investigator can see which paths are closed, which remain open and whether the environment has drifted during the search.
An example
After increasing a timeout for one test, record both the latency result and the fact that the timeout must be restored.
Check your result
A second person can avoid repeating a completed test and can reconstruct material state changes.
Keep this limit in mind
- The ledger is not a dumping ground for secrets, personal data or unverified blame.
Connected ideas
Useful withGive every postmortem action a verifiable finish
Evidence and sources
Google SRE recommends recording hypotheses, tests and observed results so investigations do not repeat work or lose the path back to the pre-test state.
Do not place credentials, regulated data or unnecessary personal information in an incident notebook.
Effective Troubleshooting · Test and Treat; investigation notes