

I had one back in the day like that. My notes on that event are old so maybe someone can modify or clarify.
First you’ll have to find the UUID of the external drive. (lsblk -f) Then create a mount file like: sudo nano /etc/systemd/system/mnt-data.mount. In the mnt-data.mount file, insert something like:
[Unit]
Description=External HDD Mount
Requires=dev-disk-by\x2duuid-<YOUR_UUID>.device
After=dev-disk-by\x2duuid-<YOUR_UUID>.device
After=local-fs.target
[Mount]
What=/dev/disk/by-uuid/<YOUR_UUID>
Where=/mnt/data
Type=ext4 # Change to ntfs, xfs, etc., depending on your drive format
Options=rw,noatime,nofail
Enable and reload:
sudo systemctl daemon-reload
sudo systemctl enable mnt-data.mount
sudo systemctl start mnt-data.mount
Verify status:
systemctl status mnt-data.mount
Should say ‘active’. Reboot and test. Let me know if that works. Like I said, that was a while ago. If it works, it’s just another reason why you should doccument your server setups. If it doesn’t, well shucks I tried. LOL

I’ll make an addenda to my notes. Thanks.