Subject: Re: /boot on RAID1: "Can't open /boot"
To: Mike Frandsen <michael.frandsen@sri.com>
From: Greg Oster <oster@cs.usask.ca>
List: netbsd-help
Date: 08/25/2007 07:53:31
Mike Frandsen writes:
> I've tried to follow the instructions in "Chapter 15. NetBSD RAIDframe"
> for booting NetBSD from RAID1.
>
> My configuration is NetBSD 3.1 over 4 250 GB SATA drives configured with:
> RAID1 root partition (mirroring across all 4 disks)
> RAID5 large partition (spanning all 4 disks)
>
> The error I'm getting when trying to boot the system is:
> Boot failed (errno 2): Can't open /boot
>
> I thought the main tricks were:
> * make sure there's a partition visible with fdisk and marked active
> * make sure / is only RAID1 (since RAID5 not supported for root
> filesystem at boot time)
> * make sure / starts at the beginning of the RAID partition
> * make sure RAID is configured to set "root" and "autoconfig" (-A root)
> * run installboot for all bootable disks
> * based on the error message, I've double-checked the "/boot" file and
> ensured it is the same as in /usr/mdec
>
> I can boot off a CD and mount the RAID partitions so I know RAID is
> working and the filesystems are ok.
>
> Is there something I'm missing or anything else I should try? Are there
> any peculiarities with RAID1 mirroring across all 4 disks instead of just 2?
Yes. A RAID 1 set across 4 disks isn't a 4-way mirror (like it
should be). It's a interleaved mirror, which means that some of
/boot may be one one disk, and the rest on another disk (or it might
be all on one or the other). Once /boot gets split up (or is all on
the disk that you didn't boot from), the initial boot code doesn't
have a clue where to find all of it..
Stick with 2 disks and you should be fine...
Later...
Greg Oster