Question
PagerDuty fires DiskUsageHigh on three of your eight primary Postgres nodes: the data volume is at 91% and climbing ~1.5%/hour. The capacity dashboard shows free space dropping in a straight line that started ~6 hours ago; throughput and connection count look normal. A feature flag enabling verbose per-request audit logging to a table was rolled out yesterday afternoon, and a nightly VACUUM job last completed two nights ago. If the volume hits 100%, Postgres will refuse writes and the app goes read-only. Walk me through how you keep the database writable in the next hour and then fix it durably.
Stop the bleeding first (mitigate), then form hypotheses from real signals. Separate root cause from symptom, communicate status as you go, and close with what prevents a repeat.