NetBSD on Raspberry Pi with LVM ?

[Dannis 't Hart <dannisthart%gmail.com@localhost>]

Hi,

If anyone is interested, I thought I'd share my little experiment with 
NetBSD on Raspberry Pi.

Already enjoying my RPi model B with linux/RaspBMC on it, I decided to 
try and build a little fileserver with a second RPi. I bought a newer 
model B+, plugged in a powered USB-hub, and attached 2 hard drives (2 TB 
each) to that. My first choice would probably be OpenBSD since I use 
that for my firewall, but from what I read, there is little chance of 
getting OpenBSD to work on RPi. NetBSD must be the next-best-thing, then 
:-)

So, this is all pretty easily done. First I tried an image evbarm from 
HEAD as found on nyftp.netbsd.org. But I found it little work to install 
VirtualBox on my Windows laptop (amd64), install NetBSD under that, and 
use the famous build.sh to cross-compile for RPi (-m evbarm -a 
earmv6hf). This all works just fine, and speedily.

But now the issue I am confronted with. I want to use LVM to 
transparantly combine partitions on 2 different disks. Although I think 
the NetBSD Guidebook and manpages are not particularly clear on it, I 
got it to work. But not satisfactorily yet, with respect to do stuff 
automatically.

I need to load the module dm (pseudo-device dm # device-mapper) for LVM 
to work. But it won't, because the securelevel is already up to 1. I can 
boot into single user mode, modload dm, and exit to multi-user. Then I 
can use LVM, although it seems I still need to manually 'vgchange -a y' 
to activate it, before I can actually mount my logical volume.

Another strange thing, I added 'pseudo-device dm' to my kernel 
configuration file, but it doesn't seem to help, it seems it is not 
included in the kernel, but still built as an LKM.

Can anyone tell me the secret incantations to resolve these little 
issues? It works for now, but I have to go via single user mode.

Thank you.

Kind regards, Dannis.