Re: /boot on RAID1: "Can't open /boot"

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