Arch Linux

manypopes

Member

Registered: 2013-06-25

Posts: 33

Do both of my HDDs need to be GPT for grub to work?

I've just began migrating from Xubuntu to Arch, installation has all gone well but I can't get grub to work properly. I've left Xubuntu installed and put Arch on to a new harddrive. I can boot from either HDD, both show grub at startup but in each case grub only shows the installation on that HDD.

I think the problem is that the Xubuntu harddrive uses MBR (I used GPT for Arch)

Type device filename, or press <Enter> to exit: /dev/sda
Partition table scan:
  MBR: MBR only
  BSD: not present
  APM: not present
  GPT: not present

Found invalid GPT and valid MBR; converting MBR to GPT format.
THIS OPERATION IS POTENTIALLY DESTRUCTIVE! Exit by typing 'q' if
you don't want to convert your MBR partitions to GPT format!

When I run " grub-mkconfig -o /boot/grub/grub.cfg " from the beginner's guide:

NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda      8:0    0 232.9G  0 disk  (Xubuntu)
├─sda1   8:1    0 229.4G  0 part 
├─sda2   8:2    0     1K  0 part 
└─sda5   8:5    0   3.5G  0 part (swap)
sdb      8:16   0 232.9G  0 disk (Arch)
├─sdb1   8:17   0  1007K  0 part (BIOS boot partition)
├─sdb2   8:18   0    15G  0 part / 
└─sdb3   8:19   0 217.9G  0 part /home
sr0     11:0    1  1024M  0 rom  

So, do both of my harddrives need to be GPT for grub to work across them or is that not the problem?

Does converting /dev/sda to GPT like gdisk says destroy Xubuntu?

If fixing this isn't possible (without formatting etc which I'd rather avoid) could I disable grub somehow so that when I boot sda it goes straight to Xubuntu and when I boot sdb it goes straight to Arch? (at the moment the grub menu serves no purpose)

Please ask me if you need any more info.

WonderWoofy

Member

From: Los Gatos, CA

Registered: 2012-05-19

Posts: 8,414

Re: Do both of my HDDs need to be GPT for grub to work?

Unless your computer firmware freaks out at the existence of GPT, you can mix and match GPT and MBR partitioning as you please.

Last edited by WonderWoofy (2013-06-25 14:25:32)

rutgerr

Member

From: São Paulo, SP - Brasil

Registered: 2011-06-06

Posts: 72

Re: Do both of my HDDs need to be GPT for grub to work?

Unless your computer firmware freaks out at the existence of GPT, you can mix and match GPT and MBR partitioning as you please.

+1

I have 2 MBR and 1 GPT disks in my system and works very well.