So I went ahead and installed an m.2 SSD in my girlfriend’s laptop and want to proceed and install the OS. She had a 1TB HDD which is /dev/sda and now the new SSD is /dev/sdb.
How do I switch them around? I want to have the SSD as /dev/sda, and the HDD as /dev/sdb. Don’t ask me why, I have no other reason besides OCD.
If the BIOS has options to assign priority to the attached drives or ports, it might be possible from there. Otherwise you could create some rules as described here:
You don’t.
Device names like /dev/sda and /dev/sdb are not guaranteed to be stable - on one of my systems they switch quite frequently.
Use /dev/disk/by-id/ or /dev/disk/by-uuid/.