Re: [gentoo-user] boot problems

[Peter Humphrey <peter@prh.myzen.co.uk>]

On Saturday 03 May 2014 20:40:47 J. Roeleveld wrote:
> On Saturday, May 03, 2014 06:09:21 PM Peter Humphrey wrote:
> > Hope I'm not butting in here, but...
> > 
> > Although I don't run systemd nor do I have an initramfs, the grub.conf
> > entry for my LVM2 setup is just these two lines:
> > 
> > title=Gentoo Linux 3.12.13
> >         kernel /boot/kernel-x86_64-3.12.13-gentoo root=/dev/md5
> > net.ifnames=0
> 
> That works with metadata=0.9 when creating the raid-1 device and not having
> " / " on LVM.

Yes, I should have added that I have /boot on straight ext2 on /dev/sda1 (sdb1 
is ready in case I decide to raid it). The file-system root is on raid1 and 
everything else is in LVs on /dev/md7, also raid1. I did it that way to keep 
booting simple. And I've used 0.9 metadata throughout.

> I only have /boot on a raid-1 with metadata=0.9.
> All the other partitions are LVs with the lvm layer ontop of a raid-0.
> (no important data is stored locally on the desktop machines)

I wanted the little extra safety of raid1 because this is where I keep all my 
data.

> > I've noticed several times (often much to my annoyance before I discovered
> > what to do about it*) that starting of the raid arrays is automatic,
> > apparently done by the kernel though I could be wrong about that. In fact 
> > I was astonished to find not long ago that I'd been running for a year or
> > two with neither lvm2 nor mdraid installed!
> 
> Something must have handled the LVM part. Afaik, there is no kernel auto-
> detect for LVM.

Yes, that's why I mentioned it. If it's not the kernel I don't know what else 
it could have been. Udev? I don't see anything relevant under /etc/udev.

> > * SystemRescueCD and the Gentoo minimal installation CD both start any
> > raid
> > arrays they find and apply their own names to them. It is then impossible,
> > or so I thought, to resume an interrupted installation process. Of course,
> > all I had to do was "mdadm --stop /dev/md127" etc.
> 
> Yes, I noticed that annoyance myself. I would much prefer it to default to
> more logical names.

If the docs had included that little snippet I'd have saved myself many a 
frustrating hour. I'll only look stupid if I tell you how many  ;-)

Anyway, I don't want to hijack the thread. I just wanted to point out that 
raid arrays don't need lvm2 or mdraid present to auto-start, at least not on 
my openrc box which also has no initramfs.

-- 
Regards
Peter