Disk full on primary
Postgres primary. Disk usage on the data volume climbed steadily over 2 days and just hit 100%; the DB is now refusing writes / crashing on `could not write to file ... No space left on device`. The `pg_wal` directory is huge. There was no traffic spike. Two weeks ago a team set up a logical-replication subscriber for a new data pipeline; that subscriber has been down for days. Triage, get writes back safely, and prevent recurrence.
What a strong answer looks like
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.
0:00 of about 40 min
Which questions mattered is sealed until you submit. Telling you now would just be handing over the edge cases.
Run or narrate your approach, then ask the coach.