[CentOS] Re: Anaconda doesn't support raid10

[Chris Croome]

Hi

On Fri 11-May-2007 at 09:38:22AM -0400, Ross S. W. Walker wrote:
> > 
> > The entire use all four disks for /boot makes no sense if two disks
> > belonging to the same mirror for the lvm go down. Please stop this
> > nonsense about surviving everything to no benefit. You can have
> > three disks fail and still have a working /boot. For what?
> 
> I think the idea of the 4 partition raid1 was more of, what else is he
> going to do with the 200MB at the beginning of each disk which he has
> because of partition symmetry across drives?
> 
> Makes sense to just dup the partition setup from one to the other and
> now with grub and a working /boot on each disk the order of the drives
> is no longer important, he can take all 4 out, play 4 disk monty, slap
> them back in and the system should come up without a problem.

FWIW this is what I did with the last server I built which had 4x500gb
drives -- a RAID 1 /boot on 4 drives. The trick for this is to edit your
grub.conf so that you can boot off any drive and run grub-install on all
4 drives, also you have to remember to manually edit your grub.conf
after each kernel upgrade to add the 3 extra disks:

 title CentOS (2.6.18-8.1.1.el5xen) Disk 0
         root (hd0,0)
         kernel /xen.gz-2.6.18-8.1.1.el5
         module /vmlinuz-2.6.18-8.1.1.el5xen ro root=/dev/VolGroup00/Root
         module /initrd-2.6.18-8.1.1.el5xen.img
 title CentOS (2.6.18-8.1.1.el5xen) Disk 1
         root (hd1,0)
         kernel /xen.gz-2.6.18-8.1.1.el5
         module /vmlinuz-2.6.18-8.1.1.el5xen ro root=/dev/VolGroup00/Root
         module /initrd-2.6.18-8.1.1.el5xen.img
 title CentOS (2.6.18-8.1.1.el5xen) Disk 2
         root (hd2,0)
         kernel /xen.gz-2.6.18-8.1.1.el5
         module /vmlinuz-2.6.18-8.1.1.el5xen ro root=/dev/VolGroup00/Root
         module /initrd-2.6.18-8.1.1.el5xen.img
 title CentOS (2.6.18-8.1.1.el5xen) Disk 3
         root (hd3,0)
         kernel /xen.gz-2.6.18-8.1.1.el5
         module /vmlinuz-2.6.18-8.1.1.el5xen ro root=/dev/VolGroup00/Root
         module /initrd-2.6.18-8.1.1.el5xen.img

If I had read this thread before I set up this machine I'd have used
RAID 6 from the rest of the space, but I used RAID 5 with a hot spare,
with LVM on top of that.

Before the machine was moved to the colo I tried pulling disks out while
it was running and this worked without a problem, which was nice :-)

Chris

-- 
Chris Croome                               <chris at webarchitects.co.uk>
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