gmirror metadata

[Paul Mather]

On Wed, 2005-03-09 at 21:22 +0100, Pawel Jakub Dawidek wrote:
> On Wed, Mar 09, 2005 at 03:03:33PM +0100, Michael Riexinger wrote:
> +> Hi, 
> +> 
> +> i have a hp dl320 with an integrated raid controller. I don't want to 
> +> use that, instead i want to use gmirror. To use the 2 IDE drives, I 
> +> configured 2 raid0 arrays (each with 1 drive) in the controller's bios. 
> +> Now i wanted to use gmirror, labeled the second drive. When I did a 
> +> reboot, the raid controller's bios seems to overwrite the gmirror 
> +> metadata with its own metadata. Is it impossible to use gmirror witch 
> +> such a configuration?
> 
> I'll be very odd if controller's BIOS overwrite disk data.

Actually, I had the same type of thing happen to me.  I put a LSI
MegaRAID IDE 100 that was lying around into my system and attached my
existing geom_mirrored drives to it.  I didn't want to use the drives as
an ATA RAID, and never set them up as that in the RAID BIOS.  I simply
wanted to upgrade from my onboard ATA 33 to the ATA 100 speed the card
supported, to get faster disk I/O.

To my surprise and regret, my system wouldn't boot properly (couldn't
locate the root filesystem) because the ATA RAID card had spammed its
metadata over the geom_mirror metadata, and my drives were no longer
detected as a geom_mirror.

Luckily, I was able to boot from a FreeSBIE CD and re-label my
geom_mirror with gmirror, thus saving my system.  It was a bit
disconcerting, though. :-)

Cheers,

Paul.
-- 
e-mail: paul at gromit.dlib.vt.edu

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