Question about "/var/lib/postgresql/data" volume

[steakhutzeee]

Hi, have a little question.

I have actually this compose file:

  pgbackups:
    image: prodrigestivill/postgres-backup-local
    container_name: paperless-ng_db_bak
    restart: unless-stopped
    user: 1000:100
    volumes:
      - /srv/dev-disk-by-label-HC2/AppData/paperless-ng_db_bak/backups:/backups
      - pgbackups_data:/var/lib/postgresql/data
    depends_on:
      - db
    environment:
      - TZ=Europe/Rome
      - POSTGRES_CLUSTER=TRUE
      - POSTGRES_HOST=paperless-ng_db
      - POSTGRES_DB=xxx
      - POSTGRES_USER=xxx
      - POSTGRES_PASSWORD=xxx
      - POSTGRES_EXTRA_OPTS=
      - SCHEDULE=@midnight
      - BACKUP_KEEP_DAYS=7
      - BACKUP_KEEP_WEEKS=0
      - BACKUP_KEEP_MONTHS=0

I checked performing a manually backup and it works.

I just don't understand why a new volume is created with the container, pointing to /var/lib/postgresql/data. In my compose file i called the volume pgbackups_data just to recognize it.

Thank you in advance!

[prodrigestivill]

This volume is created by the parent docker image (the official postgresql docker image).
It is not used by this image.

[steakhutzeee]

This volume is created by the parent docker image (the official postgresql docker image).
It is not used by this image.

Strange, here is a detailed view from portainer:

I named the volume in my compose so when i look at it i know what it is.

From my compose:

paperless-ng_db_bak:
    image: prodrigestivill/postgres-backup-local
    container_name: paperless-ng_db_bak
    restart: unless-stopped
    user: 1000:100
    volumes:
      - /srv/dev-disk-by-label-HC2/AppData/paperless-ng_db_bak/backups:/backups
      - pgbackups_data:/var/lib/postgresql/data

[steakhutzeee]

Also here you can see that the "paperless-ng_db" container has its own bind mount for /var/lib/postgresql/data:

[prodrigestivill]

Please read the docker files I attach here.

This project imports the official postgresql docker image, and this last docker image is the one that creates the volume you are asking.

But this repository makes no use of the volume you are asking, it only uses the postgresql cli programs, don't start any postgresql server.

[steakhutzeee]

Please read the docker files I attach here.

This project imports the official postgresql docker image, and this last docker image is the one that creates the volume you are asking.

But this repository makes no use of the volume you are asking, it only uses the postgresql cli programs, don't start any postgresql server.

Thanks. So it's normal to have that volume in this image. Correct?

[prodrigestivill]

Yes, it it will never be used.