How can PRTG notify me if my system can no longer copy files on my External HDD?

Hi,

you can use our SSH Script-Sensor for this.

You have to create a script with the following content in the path /var/prtg/scripts/ on your Linux-Machine:

#!/bin/bash
TOUCH="/usr/bin/touch"
RM="/bin/rm"
GREP="/bin/grep"

PATH="$1"
if [ `echo $PATH | $GREP '/$'; echo "$?"` -eq 1 ]; then
  PATH+="/"
fi
PATH+="testfile_prtg"

# check if the path exists
if [ -d "$1" ]; then
  # check if the path is writable
  if [ `$TOUCH "$PATH" 2> /dev/null; echo "$?"` -eq 0 ]; then
    # if it is writable return "1"
    echo "0:1:OK"
    # and then remove the file:
    $RM "$PATH"
  else
    # if not return "0"
    echo "2:0:Path '$1' is not writable!"
  fi
else
  # notify the user to check the path-parameter
  echo "1:0:Path '$1' does not exist!"
fi

After making it executable you can add the ssh-script-sensor in PRTG and provide the path to check as parameter in the sensor settings. If the path is not writable you will be alerted with a down-state, if the path does not exist you will see a warning-state.

Kind regards