Dual-boot two Arch OSs on same device, possible?

earthlin · 2016-11-21 02:45:30

Hello Archers,

Computer setup
GPT (not using UEFI)
sda1 BIOS boot partition ef02
sda2 /boot
sda3 swap
sda4 Arch1 Main OS
sda5 Arch2 Testing OS

First I run

grub-install /dev/sda
os-prober
grub-mkconfig -o /boot/grub/grub.cfg

I can arch-chroot into either Arch1 or Arch2
run grub-mkconfig -o /boot/grub/grub.cfg
and be able to boot into that os but not the other one

I get an error about UUID=ad41... not found
Not sure where that UUID comes from. Non of my disks have an address starting with ad.

Next I tried modifying /etc/grub.d/40_custom

menuentry "System shutdown" {
	echo "System shutting down..."
	halt
}

menuentry "Arch2 Test OS" {
	set root=(hd0,4)
	linux /boot/vmlinuz-limux
        initrd /boot/intel-ucode.img
	initrd /boot/initramfs-linux.img 
}

Both OSs show up in the boot menu along with the edit from 40_custom but only the one I run grub-mkconfig from works.

How can I clean this up and be able to boot from either Arch1 or Arch2?

If it is suppose to be different initramfs-linux.img and vmlinuz-linux how do I keep them seperate and get GRUB to recognize them properly.

Last edited by earthlin (2016-11-27 23:30:42)

fsckd · 2016-11-21 03:13:37

Sharing /boot is not a good idea if they have different kernel versions. One will overwrite the kernel of the other and if the versions are different enough, you will experience problems.

JohnBobSmith · 2016-11-21 05:37:36

If you want to have two completely separate and independent arch linux installations on the same drive, you'd have to set everything up in a dual-boot type scenario. Like arch and windows, but arch and arch. If you want to change only the kernel version, or have many separate kernels, there is a lot of great info for this on the wiki. Though they will share the base system. What happens if you take the live ISO and install arch a second time that way? I'm guessing if you want a testing OS, this is the way to go. Or, you could grab an external hard drive. Then you have your main OS on the internal drive and the experiments on the second drive. This way, you would significantly reduce the risk of wrecking something for your main setup.

To the issue at hand, I see you've already looked through the grub wiki page. I'm guessing that the the root directory is not on sda4, but instead on sda3. Thus you are finding the kernel images in shared /boot, and nothing else.

Hopefully this helped!

earthlin · 2016-11-21 12:27:34

Thank you both for replying.

I would like to set up a dual-boot Arch and Arch on the same device(sda)

sda4 has / "root" for Arch1
sda5 has / for Arch2

Can I use a shared SWAP sda3?

I did read about a seperate boot being a bad idea, but I also read to use it with the GPT and no EUFI configuration.

How can I remove the shared boot but still have both Arch installations show up in GRUB?

Please correct my thoughts on proceeding.
delete the sda2 boot partition?
(parted) set 1 boot on for sda4
arch-chroot into sda4

grub-install /dev/sda
os-prober
grub-mkconfig -o /boot/grub/grub.cfg

then exit and arch-chroot into sda5
then I don't know
I don't set sda5 as bootable
grub-install /dev/sda5 doesn't work

Do I create the kernel on sda5, if so how?

Then I would arch-chroot back into sda4 and run os-prober(or just modify the 40_custom) and run grub-mkconfig

Last edited by earthlin (2016-11-27 23:33:36)

earthlin · 2016-11-24 15:31:45

Can you dual boot two arch systems on the same device?

graysky · 2016-11-24 15:33:57

Just have /boot as part of the root file system and define them in /etc/grub.d/40_custom

menuentry 'Mini - Arch (on /dev/sda1)' --class arch --class gnu-linux --class gnu --class os {
load_video
set gfxpayload=keep
insmod gzio
insmod part_gpt
insmod ext2
set root='(hd0,gpt1)'
linux /boot/vmlinuz-linux root=/dev/sda1 rw
initrd  /boot/intel-ucode.img /boot/initramfs-linux.img
}

severach · 2016-11-25 05:48:14

I have them in folders, boot from the CDROM, and run a shell script to switch.

earthlin · 2016-11-27 23:52:28

I almost messed up my main Arch os on sda4

the steps I took

mount dev/sda4 /mnt
swapon dev/sda3
genfstab -p /mnt > /mnt/etc/fstab
arch-chroot /mnt
mkinitcpio -p linux

mkinit replied with
Error specified kernel image does not exist /boot/vmlinuz-linux

I ran my original setup, I did have to reformat sda2 that was never mounted?
restore my fstab backup
and now writing this

I think my next step is arch-chroot and pacman -S linux
What will that override on my custom os?

Is that how and the only way to create the vmlinuz-linux?

Arch Linux

#1 2016-11-21 02:45:30

Dual-boot two Arch OSs on same device, possible?

#2 2016-11-21 03:13:37

Re: Dual-boot two Arch OSs on same device, possible?

#3 2016-11-21 05:37:36

Re: Dual-boot two Arch OSs on same device, possible?

#4 2016-11-21 12:27:34

Re: Dual-boot two Arch OSs on same device, possible?

#5 2016-11-24 15:31:45

Re: Dual-boot two Arch OSs on same device, possible?

#6 2016-11-24 15:33:57

Re: Dual-boot two Arch OSs on same device, possible?

#7 2016-11-25 05:48:14

Re: Dual-boot two Arch OSs on same device, possible?

#8 2016-11-27 23:52:28

Re: Dual-boot two Arch OSs on same device, possible?

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