[Solved] Problem booting 64 bit guest on 32 bit host with VirtualBox

Sathors · 2012-08-29 14:21:35

Hi all,

sorry to bother you, but once again I'm having a tough time trying to get grub2 to boot my system.

So I did a disk cloning of an archlinux install in a .vdi disk in VirtualBox (using dd), I installed grub2 following the wiki, but after having selected my entry it just hangs with a black screen.

Here is my /boot/grub/grub.cfg file :

set timeout=5
set default=0

menuentry "ArchLinux" {
    set root=(hd0,1)
    linux /boot/vmlinuz-linux root=/dev/sda1 ro
    echo "hello"
    initrd /boot/initramfs-linux.img
}

When I added the options pager=1 and debug=all to my grub.cfg, it is stuck at a line about /lib/realocator.c

I tried regenerating the inird image by using mkinitcpio, it doesn't change anything.

I added the echo to find out at which part it got stuck, and "hello" gets outputted just before the boot hangs, so I guess there is a problem because of initramfs, but I really don't know how to debug this.

Thank you for your help !

Sathors

Last edited by Sathors (2012-08-30 13:59:11)

DSpider · 2012-08-29 14:28:36

So I did a disk cloning of an archlinux install in a .vdi disk in VirtualBox (using dd)

Can you be more clear?

You cloned a... partition? The MBR is installed to /dev/sdx, not dev/sdxY.

Sathors · 2012-08-29 14:40:09

DSpider wrote:

Can you be more clear?
You cloned a... partition? The MBR is installed to /dev/sdx, not dev/sdxY.

By following the wiki, I cloned a partition like that :

 dd if=/dev/sdb6 of=/dev/sda1 bs=4096 conv=notrunc,noerror

Then I tried to clone the MBR too, by using this line :

dd if=/mnt/sdb of=/dev/sda bs=446 count=1

(bs=446 because I just needed the bootloader).

As it wasn't working, I decided to install grub2 from fresh using the dedicated page on the wiki.
To be precise I installed it using the method "Install to 440-byte MBR boot code region"

Last edited by Sathors (2012-08-29 14:40:26)

DSpider · 2012-08-29 15:09:47

Use rsync instead of dd.

https://wiki.archlinux.org/index.php/Fu … with_rsync

I still don't understand what you're trying to do: get an installed Arch Linux out of VirtualBox, or get an existing install into VirtualBox.

Sathors · 2012-08-29 15:12:57

I have an Archlinux installed on my usb key, and I cloned it on virtualbox to be able to use linux at work (on a windows XP system).

I think I'll try to use rsync tomorrow.

Thank you for your help though !

Sathors · 2012-08-30 10:11:00

Hum, it is still not working, and I still have the same behavior ...

So I cloned my disk using rsync this time, and I still have the same problem, it hangs at the same moment, just after launching the selected entry.

I don't know if it's because of VirtualBox, I changed all the options I could on the virtual machine configuration, but it doesn't change anything.

I am quite at a loss here !

Thank you.

DSpider · 2012-08-30 11:03:43

I think it's because the hardware has changed since moving from a virtual machine to an actual machine, and the initramfs loads different modules now (e.g. SATA instead of the default IDE from VirtualBox).

Try the Fallback entry and then rebuild your initramfs image with:

# mkinitcpio -p linux

Basically, the first method from: https://wiki.archlinux.org/index.php/Pa … onger_boot

And don't forget to mark the topic as solved.

Sathors · 2012-08-30 12:45:46

Okay,

so now I come to you after a few more experiments.

I tried to rebuild the image with mkinitcpio, but as I'm doing it from the archlinux live cd, I cannot use the preset and I have to specify all the paths in the options of mkinitcpio. But it seems to work fine, without errors.

I still have the same problem though.

What I discovered, is that the system I have cloned is a 64 bit install, and I had to make some changes to the Virtualbox configuration to allow 64 bits support.

The problem is that I cannot chroot into my fresh install from the live-cd, because now the archlinux livecd is 32 bits, so when I try to chroot I have the 'Exec format error'.
Is there any way to boot the livecd in 64 bits ? Or is there any other way to chroot into a 64 bits system from a 32 bits system ? So far from what I have gathered on the Internet the latter is not possible.

I think everything would be easier for me once I can chroot into my fresh install.

What bugs me is that I don't have any trace on the possible error ...

Thank you for your help

DSpider · 2012-08-30 13:20:57

The Arch Linux ISO images released in 2012 contain both i686 and x86_64 architectures. But you won't see the "Boot Arch Linux (x86_64)" entry with a 32 bit CPU or if you're trying to boot the ISO in VirtualBox where the host OS is 32 bit.

If the computers at work do not meet this requirement, then you should "freshly install" Arch i686. That will guarantee you (to some extent, obviously) that it will boot on both 32 bit and 64 bit machines.

Last edited by DSpider (2012-08-30 13:39:53)

Sathors · 2012-08-30 13:57:56

Ok, so now I got it.

It's clearly stated in the virtualbox faq that running a 64 bit guest on a 32 bit host is possible, provided that the cpu is 64 bit capable, and that you activated AMD-V/VT-X in the BIOS.

But it seems there have been bugs and issues on this (this thread for example is quite old, but the problem is quite the same).

I tried also a 64-bit livecd of linux mint, and when run with the default entry it hangs right at initramfs loading, but in compatibility mode at least I have a clear error which tells me that the cpu is not 64 bits compatible. It's sad that archlinux doesn't rise this error too, it would have avoided me much pain and searching in wrong directions !

So thank you for your help, I think I'll do a fresh install.

Arch Linux

#1 2012-08-29 14:21:35

[Solved] Problem booting 64 bit guest on 32 bit host with VirtualBox

#2 2012-08-29 14:28:36

Re: [Solved] Problem booting 64 bit guest on 32 bit host with VirtualBox

#3 2012-08-29 14:40:09

Re: [Solved] Problem booting 64 bit guest on 32 bit host with VirtualBox

#4 2012-08-29 15:09:47

Re: [Solved] Problem booting 64 bit guest on 32 bit host with VirtualBox

#5 2012-08-29 15:12:57

Re: [Solved] Problem booting 64 bit guest on 32 bit host with VirtualBox

#6 2012-08-30 10:11:00

Re: [Solved] Problem booting 64 bit guest on 32 bit host with VirtualBox

#7 2012-08-30 11:03:43

Re: [Solved] Problem booting 64 bit guest on 32 bit host with VirtualBox

#8 2012-08-30 12:45:46

Re: [Solved] Problem booting 64 bit guest on 32 bit host with VirtualBox

#9 2012-08-30 13:20:57

Re: [Solved] Problem booting 64 bit guest on 32 bit host with VirtualBox

#10 2012-08-30 13:57:56

Re: [Solved] Problem booting 64 bit guest on 32 bit host with VirtualBox

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