Selfhosted

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

That risks breaking the drive eventually. They don’t handle loss of power well. And if its being written to at the time, data loss and corruption is inevitable.

That said, no need to reboot to mount the drive.

sudo mount -a

Remove the laptop battery.

/jk

I used to have a similar setup and the disk didn't last a year. All those power losses are going to break the disk eventually. Now I'm trying a cheap UPS.

I recommend a UPS, even a small one is fine for this. Spinning disks don't like frequent starts and stops, especially not unplanned powerless ones.

At least you should be running a journaling file system or something similar which tolerates power loss decently (you'll still see data corruption, but the file system won't die). If you run software that doesn't tolerate power loss well, then you absolutely need an UPS

I can infer that you want suggestions for cost efficient backup power. Depending on the laptop model, it could power the HDD and in case of an outage it could draw power from the laptop's battery. It would decrease battery charge duration but it would be enough for a graceful shutdown to prevent data loss.

Alternatively, you could maybe use a battery pack.

In short: buy a cheap ups power strip or a generous USB powebank capable to being under charge 24/7 and do not let the HDD switch off on power loss...

That is a guaranteed recepy to destroy your data and possibly the hardware as well as spinning disks don't like abrupt shutoff and that applies to data being written on SSDs as well.

Remounting after the power resumes is the last of the issues, easily fixed by a amount/mount command with the proper fstab setup.

Cheap and dirty solution would be a battery backup for the drive, but there are some big concerns about the setup. Drives don't like to go dark like that.

Does anyone know how I can resolve this issue?

I don't know why you'd need a reboot to remount the thing. Are you just not familiar with how to add something to /etc/fstab and mount it manually and are relying on some kind of auto-mounting system that only happens to run at boot, or is it giving some kind of error?

If an error, what happens when you do:

$ sudo mount -o remount /mnt/the-mount-point

?

Autofs might do what you're looking for. How often do you have power outages that it's a major concern?

First step is to not use a laptop with a charged/charging battery in it as an always-on server. Terrible idea.