[SOLVED] Multibooting OMV 4 and OMV 5 on External USB drives.

I wish to be able to multiboot between two versions of OMV.

I have OMV 4 and OMV 5 installed to separate 16GB SSDs housed in identical external USB cases. fstab entries for each drive are as follows:

/dev/disk/by-label/ssd-omv5 / ext4 noatime,nodiratime,errors=remount-ro 0 1

/dev/disk/by-label/ssd-omv4 / ext4 noatime,nodiratime,errors=remount-ro 0 1

If I connect either of the drives to the box, they boot fine.

If I connect both drives to the box and use the system boot menu to select the boot device, I will see the appropriate kernel lists fine (they are different due to one having kernel 5.3 available).

Depending on which drive I select in the system boot menu, it either boots fine or I get a message that the kernel can not be found.

Is what I am trying to do really possible?

Thanks for any ideas you might have.

Zitat von ryecoaaron

The problem here is update-grub only updates the /boot files on one stick. So, unless you run it while booted into each system, you will get the grub menu from one stick and it may list a kernel that isn't on the other stick. If I was going to do this, I would probably put the /boot filesystem and grub boot loader on a third stick.

I did update-grub while booted to both systems. As I said, the grub menu kernel lists that are displayed are full and correct for each system.

Both systems have all the kernels in their respective boot menus available for use. They both fully work as expected when only either one is plugged in. It only misbehaves when both drives are plugged in.

I managed to get it to boot with both drives are plugged in and I select one or the other from the system boot menu. But what it is doing is booting to the OMV 5 disk, even when I select the OMV 4 disk. I do see different lists of kernels depending on which drive I select. So it is looking at the correct disk in the beginning.

Both disks still have the same UUID for their partitions. Is this even relevant anymore since I am booting by disk label now?

I looked in the file /boot/grub.cfg. That UUID is plastered all over the place. Like in 146 places. LOL.

I have to leave for now but when I get back I am going to change the UUID on one of the disks and regenerate grub.

OK, I got it working! The duplicate UUID was the culprit.