Linux – Do I need two /boot partitions for a dual boot system


The current partitioning as shown in Gnome Disks is:

/dev/sda1 Linux Bootable 500mb
/dev/sda2 Linux LUKS Encryption 478gb (this is LVM)
Free Space 21gb

In /dev/sda2, there is /, swap and /home.

I want to install another distribution on the 21gb free space. It will share swap and home partitions with the current installation.

I will mount /home and swap as respective mountpoints and not format them. I will create / for the new distribution.

The question is what do I do with /boot? Do I use the existing one or a new one?

Also, do I need to install GRUB again? Where?

Best Answer

Yes, you can share the /boot partition with multiple distributions, but it's not trivial. In order to avoid possible conflicts I'd only use ONE of them (typically the one with the most recent/up2date GRUB version) to "own"/configure/manage it. To prevent accidental damage I'm even mounting it readonly in the "non-owner" distributions (or not mounting it at all).

It may be a bit tricky to install the subsequent distributions without affecting the previous ones. Especially if handing over the /boot partition "ownership" to the newer installation. Personally I prefer to NOT use a separate /boot partition for the newer installation (temporarily making its / partition the bootable one) and manually "merging" it's /boot directory info into the shared /boot partition scheme after the installation. Updating a "non-owner" distribution also requires baby-sitting.

Always make backups copies of the /boot directories and the '/boot' partition along the way and have a bootable media ready for recovering the GRUB setup if something goes wrong.

Another approach is simply to not have separate /boot partitions for newer installation and simply chainload their / partitions (where their /boot directories reside) into the current GRUB scheme just like (older) Windows installations.

Be careful for possible issues with sharing the swap and /home partitions, here would be some Q&As you may want to go through for things to consider:

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