Re: software mirroring of boot drive

[Mark Dadgar <mark justracing com>]

On Jun 25, 2004, at 9:16 AM, Grunloh, Robert wrote:
> However if, as a test, I tell the scsi card's bios to boot off of the 
> 2nd
> drive it just hangs (no errors) before the grub menu appears. Same 
> behavior
> if I unplug the first drive. If I unplug the 2nd drive it boots ok but
> complains about degraded mode, as expected.
>
> I suspect the partitions are mirrored but grub isn't properly 
> installed on
> the second drive's MBR or isn't aware of it. However I can't seem to
> unmirror them to work on the problem, since they're in use, not that 
> I'm
> good with grub anyway. -- I must be missing something obvious.

dd if=/dev/sda of=/dev/sdb bs=512 count=1

The MBR is stored in the first 512 sector of the hard drive.  This 
sector is not part of any partition, so you won't overwrite anything 
else by doing this.

YMMV, of course.  Standard disclaimers apply.

- Mark
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