exFAT and mounting SSD method

[JD1]

An update to my woes:
Both OS disk SSD and music SSD formatted with Ext4. Somehow I managed to get the OS disk as sda1 and the music disk as sdb1. Still there was a problem when I tried to copy music files via Samba. My Mac saw the 2TB music SSD as being only 50GB (size of OS disk). I got around that my plugging the music SSD directly into my Mac and copying files into it that way.

Now, one problem remains:
When I start up my Snakeoil server, it most often does not recognise both disks...but sometimes it does. It might recognise only OS disk or only Music disk
in BIOS it will typically not show either disk as a boot option and may or may not show one or the other disk as an attached SATA drive. However, if I press F12 during start up, it will typically show both disks as options for booting from...and I can start it that way.

So BIOS sees the disks in some respects but not in others and is not sure where to boot from. This is despite setting OS disk as Boot Option 1 and having no USB drives connected. The next time I boot into BIOS, the Boot Option menu is likely not even accessible as that part of BIOS does not see any drives at all.

Any suggetions?

Cheers,
JD