I have a very simple setup which is based on two hard drives, let's call them sda and sdb. I want to have two different distributions on those hard drives, one based on Ubuntu and another based on Xubuntu for example.

Now reading about the Linux Boot Process, I get that the GRUB is loaded from the MBR and is used to select the kernel you want to load among other things.

But if I have two different drives, can I have two different GRUB with two different configuration files?

  • I have two different drives .... yes, but only one is bootable, so you have one copy of grub ..... the system on the second drive gets to have an entry in the grub boot menu
    – jsotola
    Commented Jan 29, 2019 at 0:15
  • 1
    Or you could switch the active drive (sdb) on bootup with a hot key (F12 or whatever key your bios wants) and install grub this way on both drives. And then add an "extra" entry for the missing drive to each installation. This way you will always have the possibility to boot the "other drive" with the function key.
    – Freddy
    Commented Jan 29, 2019 at 1:09
  • Exactly the setup that I was looking for. Two drives, two installs of Grub, but I didn't think about adding each grub a reference to the other drive for simpler boot. Thanks. Commented Jan 29, 2019 at 6:34

1 Answer 1


GRUB comes into picture only when multiple OSes installed on one physical drive (dual boot).

Physical drive selection is as per the priority order in the BIOS. Even before GRUB comes into action, one of the physical drives is already filtered out.

So you have two different GRUBs for two physical drives.

  • You might want to also mention that any modern hardware uses the UEFI firmware to decide boot order, which is a different mechanism than the old (CSM, legacy) BIOS boot.
    – jsbillings
    Commented Feb 14, 2021 at 14:33
  • Thanks for mentioning that, I thought that, regarding the priority order selection, both Legacy BIOS and UEFI BIOS works the same even though both are completely different in the way they work in managing the partitions.
    – Sumanth
    Commented Feb 14, 2021 at 15:23

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