Subject: Re: grub vs. raidframe
To: None <>
From: Mike M. Volokhov <>
List: port-xen
Date: 11/10/2005 14:46:46
On 11/02/2005 14:34:18 EET Jeff Rizzo wrote [not subscribed to port-xen
before so this is not followup, sorry]:

> I recently had occasion to want to run Xen on a system with mirrored
> root disks (mmm, RAIDframe), and whereas a message from around a year
> ago hinted at how to do it, the details were left as an exercise to
> the reader.  Since I've just gone and done it, I thought I'd share
> the recipe here for the enlightenment of others in the same boat.
> (and also because I'm likely to forget details myself!)

Yeah, that's me :-)

> I hope this helps somebody else

It really was, thanks in advance!

But I would like to add few comments more.

So, once again:

1) GRUB must be installed to FFS partition (which is shifted to 64
blocks from the start of RAID1 one).

2) GRUB should be installed natively, not via grub-install (see for details).

And what you have missed in my opinion, that it is a RAID, so:

3) GRUB must be installed on *all* disks of the RAID set.

But before doing this we should determine what's a sort of disk
failures we're waiting and how we would respond on them. For examlpe,
I assume that if one of mirrored HDD will be failed, we will shutdown
the Dom0, replace a failed disk and boot up again from live HDD. (See
the reason?) This means that disks must be mirrored at all levels.) So
my /grub/menu.lst contains the following lines (stripped):

title Xen 2.0.7 / NetBSD 3.0 (HDD1)
  kernel (hd0,g)/xen.gz dom0_mem=65536 
  module (hd0,g)/netbsd root=/dev/hda1 ro console=pc
title Xen 2.0.7 / NetBSD 3.0 (HDD2)
  kernel (hd1,g)/xen.gz dom0_mem=65536 
  module (hd1,g)/netbsd root=/dev/hdb1 ro console=pc

title NetBSD/i386 3.0, MP ACPI (HDD1)
  root (hd0,g)
  kernel --type=netbsd /netbsd-GENERIC.MPACPI
title NetBSD/i386 3.0, MP ACPI (HDD2)
  root (hd1,g)
  kernel --type=netbsd /netbsd-GENERIC.MPACPI

title NetBSD chain (HDD1:0)
  root        (hd0,0)
  chainloader +1
title NetBSD chain (HDD2:0)
  root        (hd1,0)
  chainloader +1

And have ran the following commands in the GRUB:

grub> root (hd0,g)
grub> setup (hd0)
grub> root (hd1,g)
grub> setup (hd1)

And last one note:

4) Should we add these explainations to Ports/xen/howto.* ?


P.S. Thanks once more, this definitively saves me lot of time and
nerves :-)