I have an Ubuntu 15.10 running on a MSI B75MA-P45 motherboard with a number of connected SATA discs. (plus one external USB-disc)
I have a small 200 GB as boot disc, one 250 GB which I have emptied and two 3TB discs for media. (plus one small 80 GB disc that doesn't even show up on my system).
Anyway, the two 80GB and 250 GB are not used so I want to remove them to reduce the heat in the box.
My problem is that when I remove them, my systems fails to boot and I get stuck in a boot menu with several options of older kernels to boot with, none of will boot though.
The only way I can boot my system is to reconnect the two drives again
This starts to drive me nuts!
Does anyone heard of this before and can point me in a direction for a solution?

// T

Your system uses the boot sector of either the 80Gb or 250Gb. Check which. You can tell it by removing only one of the two, which of them boots.

The clean solution for this is to re-install the boot loader to the disk you wanted to dedicate, then can you only remove the two small disks and continue booting with the new bootloader at the dedicated disk. If you are using grub then grub-install it to /dev/sda<dedicated> hard drive. Then "update-grub" to make it aware of available bootable kernels. When it is done... Remove the two hard drives, and... Reboot.

Hope that helps. Goodluck.

What boot manager are you using? Or are you using the USB or Cd?

grub 2.0. No cd or usb

try to reinstall grub bootloader onto your boot disk (I have a small 200 GB as boot disc) and tell bios to use that to boot.

My thoughts...

All your disk mounts are held in fstab, when you disconnect a disk and try and reboot the system without it, it'll hang trying to mount a non-existent disk. You'll need to unmount your two drives and comment them out of fstab before shutting down, removing them and rebooting.

Play Bonny!

If you change what is mounted as / or /boot or /usr in the fstab, it will be overridden by initrd. Solution is mkinitrd

@ Pyrotech72

From this I take that the Op doesn't have /, /boot or /usr on either of the two disks. Will initrd still overide fstab?

Play Bonny!

I have another possible explanation: The system is identifying drives by node "for example /dev/sda1" and because the other drives are removed these have changed. So the system boots to GRUB then GRUB can't find anything to boot to because it's looking in the wrong place. First things I'd do is check that fstab is using labels or UUIDs rather than the node. It's still possible there will be an issue with GRUB but it's worth a try.

1 members found this post helpful.

Those three are mounted with the information in initrd. (It has to know where / is to find fstab.) Hopefully, initrd doesn't search by node. I don't yet know enough about it to know whether it ever would.

Yes, the fstab is the first place to check. Try that first, along with making sure grub is installed on the desired device. Then only if we have to we'll see what we can do about initrd.

I don't know if you can help me out here, but this is what my fstab looks like:

# / was on /dev/sda2 during installation
UUID=2b96cae3-ec03-4137-ade5-cded72fc182a / ext4 errors=remount-ro 0 1

# /boot/efi was on /dev/sda1 during installation
UUID=D954-A1A4 /boot/efi vfat defaults 0 1

# swap was on /dev/sda3 during installation
UUID=9075da08-c6a0-4ff7-84c4-6f0ea12ed1e4 none swap sw 0 0

# second disk
/dev/sdb1 /media/Filmer ext4 defaults 0 2

sda1, sda2 and sda3 are on the same physical disc

sdb1 is the one I want to remove (or sdb to be more precise since all partitions are removed from that disk) so I can remove that entry from the fstab, right?

The big problem I have is that the 80GB disc doesn't appear anywhere, neither in Ubuntu nor in BIOS.

// T

Your fstab is using UUIDs so that looks fine. Yes, you could comment out the entry for sdb1 in fstab -- it could also just be that the boot process is failing because it can't mount that drive which happens sometimes.

agreed.

# second disk
#/dev/sdb1 /media/Filmer ext4 defaults 0 2