How to restore a Nextcloud PostgreSQL database

Nextcloud on aux uses Postgres inside the compose stack (nextcloud-db-1), data bind-mounted at ~/nextcloud/db/. Do not confuse this with host postgresql@16-main unless you have knowingly moved the DB.

Prerequisites

• Maintenance window (users locked out or in read-only)
• A known-good dump or restic snapshot
• Disk space for a second copy of ~/nextcloud/db

Steps (logical dump)

1. Stop the app (keep DB up for dump/restore as needed):

   cd ~/nextcloud
   docker compose stop app

2. Take a safety copy of current DB files (if disk allows):

   cp -a ~/nextcloud/db ~/nextcloud/db.bak-$(date -u +%Y%m%dT%H%M%SZ)

3. Restore from SQL dump (example):

   # dump was created with:
   # docker exec -t nextcloud-db-1 pg_dump -U nextcloud nextcloud > nextcloud.sql
   cat /path/to/nextcloud.sql | docker exec -i nextcloud-db-1 psql -U nextcloud nextcloud

4. Start app and watch logs:

   docker compose start app
   docker logs nextcloud-app-1 --tail 50 -f

Steps (restic file-level)

1. Restore ~/nextcloud/db and ~/nextcloud/config from snapshot to a temp path.
2. Stop stack: docker compose down.
3. Replace directories carefully; fix ownership if required by the postgres image user.
4. docker compose up -d and run pg_isready.

Verify

docker exec nextcloud-db-1 pg_isready -U nextcloud
curl -sI https://cloud.cadenceworks.tech | head -5

Log in as a known user and open a recent file.

Related

• Backup with restic
• Nextcloud reference