Drill: event log disk full

Overview


Module	`ops.11` · drill · ops, docs · Pass 11 · 1 to 2 h
You build	docs/runbooks/EventlogDiskFull.md
Tests	`course/tests/ops.11` (named below, with why each exists)
Needs	none
Used by	no code call site; this is an independent artifact
Milestone	`MS-P11`

Key Takeaways

Tie each claim to the exact platform evidence that Drill: event log disk full produces.
State the owner, success condition, and recovery action before declaring the work complete.
Record unresolved assumptions so the next review can test them.

How to work this chapter

ol start ops.11
ol tests ops.11
ol check ops.11

1. Why now

A full event-log disk can stop workflow progress and risk losing acknowledged work. The WAL quota provides a controlled boundary.

2. Principles

An append is acknowledged only after its durability point. Reject new work cleanly at quota, preserve readable history, and alert before the filesystem is exhausted.

3. Worked example

Fill the test WAL to its configured limit. Confirm the next append fails with RESOURCE_EXHAUSTED and no workflow reports success for it. Free or expand space and resume.

4. The artifact and its check

Test	KIND	Checks	Why it matters downstream
`test_artifact_paths_are_declared`	artifact	Confirms the submitted paths and required evidence exist, so a plausible narrative cannot pass without the reviewable deliverable.

5. Pitfalls

#	Pitfall	Symptom	Caught by
1	The canary advances before the rollback trigger is recorded	The exercise reports success without proving the old format or route can be restored.	`test_artifact_paths_are_declared`
2	The team watches request errors but omits the migration-specific signal	A partial rollout can corrupt or strand work while the generic health check stays green.	`test_artifact_paths_are_declared`
3	No owner records the decision and verification evidence	The next on-call cannot tell whether the incident is contained.	`test_artifact_paths_are_declared`

6. Where it’s used next

Direction	Module	Connection
Back	`ops.10`	Read this declared prerequisite before producing the artifact; use it to verify the relevant contract or evidence.
Back	`dur.01`	Read this declared prerequisite before producing the artifact; use it to verify the relevant contract or evidence.

Going further

Resource	What to inspect
Incident drill catalog	Compare this inject with the adjacent failure drills and use the same containment and verification fields.