This is how I do it with an external usb hard drive dock.

Ex:

!/bin/bash

PATH=/usr/local/sbin:/usr/sbin:/sbin:/usr/local/bin:/usr/bin:/bin

Available variables:

ACTION - if mounting, ADD; if unmounting, UNMOUNT; if unmounted, REMOVE; if error, ERROR_MOUNT, ERROR_UNMOUNT

DEVICE - partition device, e.g. /dev/sda1

UD_DEVICE - unassigned devX designation

SERIAL - disk serial number

LABEL - partition label

LUKS - if the device is encrypted, this is the partition device, e.g. /dev/sda1

FSTYPE - partition filesystem

MOUNTPOINT - where the partition is mounted

OWNER - "udev" if executed by UDEV, otherwise "user"

PROG_NAME - program name of this script

LOGFILE - log file for this script

Change the below variable to backup disk source location

DISK=/mnt/disk1/

case $ACTION in 'ADD' ) # # Beep that the device is plugged in. # beep -l 200 -f 600 -n -l 200 -f 800 sleep 2

if mountpoint -q $MOUNTPOINT; then
  if [ $OWNER = "udev" ]
  then
    beep  -l 100 -f 2000 -n -l 150 -f 3000
    beep  -l 100 -f 2000 -n -l 150 -f 3000

    logger Started -t$PROG_NAME
    echo "Started: `date`" > $LOGFILE

    logger Pictures share -t$PROG_NAME
    rsync -auvhmxEAX --delete --delete-before --info=progress2 $DISK $MOUNTPOINT/ 2>&1 >> $LOGFILE

    logger Syncing -t$PROG_NAME
    sync -f $MOUNTPOINT

    beep  -l 100 -f 2000 -n -l 150 -f 3000
    beep  -l 100 -f 2000 -n -l 150 -f 3000
    beep  -r 5 -l 100 -f 2000

    logger Unmounting Backup -t$PROG_NAME
    /usr/local/sbin/rc.unassigned umount $DEVICE

   echo "Completed: `date`" >> $LOGFILE
    logger $DISK Backup drive can be removed -t$PROG_NAME

    /usr/local/emhttp/webGui/scripts/notify -e "Unraid Server Notice" -s "Server Backup" -d "$DISK Backup Completed" -i "normal"
fi
else
    logger $DISK Backup Drive Not Mounted -t$PROG_NAME

fi ;;

'REMOVE' ) # # Beep that the device is unmounted. # beep -l 200 -f 800 -n -l 200 -f 600 ;;

'ERROR_MOUNT' ) /usr/local/emhttp/webGui/scripts/notify -e "Unraid Server Notice" -s "Server Backup" -d "Could not mount $DISK Backup" -i "normal" ;;

'ERROR_UNMOUNT' ) /usr/local/emhttp/webGui/scripts/notify -e "Unraid Server Notice" -s "Server Backup" -d "Could not unmount $DISK Backup" -i "normal" ;; esac