System sensor not reading second disk

Hi all. New user here. Home Assistant Docker.
Trying to use sensor,disk_free and having problems reading a second disk. The one mounted on /mnt/SATA2

My configuration.yaml

# System monitor
sensor:
  - platform: systemmonitor
    resources:
      - type: disk_free
        arg: /mnt/SATA2
      - type: disk_free
        arg: /
      - type: memory_free
      - type: load_15m
      - type: processor_use
      - type: processor_temperature
      - type: last_boot

Everything works perfectly but the second disk.
image

I have this error log

Logger: homeassistant.components.systemmonitor.sensor
Source: components/systemmonitor/sensor.py:568
Integration: systemmonitor (documentation, issues)
First occurred: 18:48:04 (309 occurrences)
Last logged: 20:05:04

Error updating sensor: disk_free (/mnt/SATA2)
Traceback (most recent call last):
  File "/usr/src/homeassistant/homeassistant/components/systemmonitor/sensor.py", line 379, in _update_sensors
    state, value, update_time = _update(type_, data)
  File "/usr/src/homeassistant/homeassistant/components/systemmonitor/sensor.py", line 478, in _update
    state = round(_disk_usage(data.argument).free / 1024 ** 3, 1)
  File "/usr/src/homeassistant/homeassistant/components/systemmonitor/sensor.py", line 568, in _disk_usage
    return psutil.disk_usage(path)
  File "/usr/local/lib/python3.9/site-packages/psutil/__init__.py", line 1995, in disk_usage
    return _psplatform.disk_usage(path)
  File "/usr/local/lib/python3.9/site-packages/psutil/_psposix.py", line 169, in disk_usage
    st = os.statvfs(path)
FileNotFoundError: [Errno 2] No such file or directory: '/mnt/SATA2'

Did you bind-mount the host‘s mount point /mnt/SATA2 into the container at the same path?

Nope, but neither did with /, and it works.

Edit: Just did that and it works. Thx.

Because a container always has a root file sytem, I’d guess you cannot even bind-mount anything to / . Anyhow - works.

can you share how to do this?

Add

-v /mnt/SATA2:/mnt/SATA2

to your docker run call.

tried that, still shows up as 0,

here is my config.yaml

- platform: systemmonitor
  resources:
    - type: disk_use_percent
      arg: /
    - type: disk_use
      arg: /
    - type: disk_use
      arg: /mnt/usbt4
    - type: disk_use_percent
      arg: /mnt/usbt4

and my docker compose:

version: '3'
services:
  homeassistant:
    container_name: homeassistant
    image: "ghcr.io/home-assistant/home-assistant:stable"
    volumes:
      - /home/user/homeassistant/config:/config
      - /mnt/usbt4:/mnt/usbt4
      - /home/user/homeassistant/config:/media
      - /run/dbus:/run/dbus:ro #bluetooth adapter
    restart: unless-stopped
    privileged: true

Looks correct, must be something else.