From: Raimo Niskanen (raimo+openbsderix.ericsson.se)
Date: Wed Aug 20 2008 - 05:19:06 CDT

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On Wed, Aug 20, 2008 at 10:01:10AM +0200, Christophe Rioux wrote:
> I follow some documentation for building the software raid on my system:
> http://www.argon18.com/raid_openbsd.html
> http://www.openbsd-france.org/documentations/OpenBSD-raid1.html#deux
>
> And the result is, I have 2 disk which are working in RAID-1. I build
> following configuration:
>
> Physical disk: 250 Go (2 x)
>
> Disklabel: wd0 and wd1
> wdXa: 10 Gb
> wdXb: 512m
> wdXd: the rest of the disk
>
> => as far I undestand, the wdXa disk are needed to boot before starting the
> RAID. This are more or less lost disk place ?
>

Yes. 10 GByte is more than sufficient for building the RAID kernel.
I have done it in 1.5 GByte, but that was maybe pushing it a bit far...

>
> I build again the same disklabel on the raid0 disk:
> a: 20971853 235680435 4.2BSD 2048 16384 1
> b: 1048576 256652288 swap
> c: 466350720 0 unused 0 0
> d: 208649856 257700864 4.2BSD 2048 16384 1
> i: 1000974 136512000 MSDOS
> j: 4017 235676418 unknown
>
> But the result is:
> a: 10 Gb
> d: 100 Gb
> i ????
> j ????

What result is?
How did you build the disklabel?
What is the actual printout from "disklabel -p m raid0"?
Oh, and "disklabel -p m wd0", and "disklabel -p m wd1"
What does "raidctl -s all" say?

>
> When I start the system, I have the feeling that I'm booting on the wd0a
> disk, and not on the raid0a disk
>

You need to make the RAID auto-configurable, and root partition
eglible. I.e "raidctl -A yes raid0" and "raidctl -A root raid0".

Read "man raidctl", all the way down to the end. It is invaluable.

> Questions:
> * how can I be sure I'm booting on the right disk ?

Check your dmesg and see which root device it uses at the end.

> * where are my 130 Gb lost place ?

You can probably find them in the disklabels.

> * where will the system write the logs down ? Wd0a or raid0a ? If those
> information are writing to raid0a, that means, I can reduce the wdXa disk to
> the minimum requirements (1 Gb for example)
>
> Christophe

--

/ Raimo Niskanen, Erlang/OTP, Ericsson AB

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