Re: Boot from LVM2 on RAID1 on 2xRAID5

[Guntsche Michael]

On Jul 28, 2008, at 11:31, Richard Michael wrote:

> Hello list,
>
> Apologies if this is a "support" question that doesn't belong on the
> devel list.  (I've been looking into RAID/LVM improvements in grub2  
> and
> thought this list might be appropriate, however.)
>
> I have a linux system with 8 disks.  I would like to divide them into
> groups of 4 and create 2 RAID5 arrays; then run a RAID1 array across  
> the
> two RAID5 arrays; and finally LVM2 on top of the RAID1 array.
Why not use Raid-10 instead of this more complex setup?


> Can grub2 boot such a nested configuration?  If so, what special steps
> must I take to install the bootloader?  (I'll install the system with
> grub-legacy using Fedora or another distro, then migrate to grub2.)

I played around with this myself a little bit. Currently Grub2 only  
understands the RAID superblock version 0.90.
Since this only supports up to 2TB of RAIDs I actually have to  
partitions on every disk. The first one is part of a RAID-1
with a 0.90 superblock. The other partition is part of a RAID-5 with a  
1.0 superblock.
Nevertheless you really should think about setting up a RAID-10  
instead. (+ a small /boot RAID-1 partition)


Kind regards,
Mike