The manual acted like this was kind of a niche thing to do, in the odd case that you would want to shut down the PC. I only use one set of peripherals, so…
So the options are to remount the partition every boot, or modify the /etc/fstab file.
I backed up the fstab file in the incorrect manner just to have a copy of it:
cd File_Backups
cp /etc/fstab .
The line in the LFS manual to add is:
/dev/sda3 /mnt/lfs ext4 defaults 1 1
The first 1 is “dump setting” enabled (1). The second 1 is Fsck setting (root). Google AI Mode says yes, the Fsck setting for LFS partition should be root.
After some reading I decided to use the UUID instead of the device name.
I found the UUID of the partition:
sudo blkid
Highlight to copy the UUID – highlight the text you want to copy using your mouse.
Copy: Press Ctrl + Shift + C
Get into the fstab file:
sudo nano /etc/fstab
Add line
UUID=x-x-x /mnt/lfs ext4 defaults 1 1
Paste in the UUID
Paste: Press Ctrl + Shift + V
Test the mounts before rebooting.
The best practice is not mount -a (thanks to Google AI Mode) but:
sudo findmnt --verify --verbose
The result suggests reloading before rebooting, with:
sudo systemctl daemon-reload
which I do. Then I reboot and check “mount”. Everything ok.