[clug] Robust bootloader setups?

Darren Freeman daz111 at rsphysse.anu.edu.au
Thu Feb 17 07:53:50 GMT 2005


On Thu, 2005-02-17 at 18:00, Michael James wrote:
> Given:
> A Suse system built on mirrored disks,
>  ( using md for software raid ).
> A separate /boot partition formatted ext2.

In my experience on the latest Mandrakes, you don't need a separate
/boot for mirroring.

What appears to happen is that half the mirror gets mounted read-only,
the RAID starts, then the system mounts read-write off the RAID. Or
maybe LILO just remembers which sectors to find the kernel in, or
perhaps it has basic filesystem code for reading those files.

It's not far off being a wild guess but it fits my experience.

Beware of boot CDs like Knoppix and the Mandrake rescue, that mount half
the RAID as read-write! Since the OS isn't aware of the RAID it never
gets set dirty! So next time you boot you can end up with a really
screwed filesystem (I know, I've been there) because the RAID is out of
sync. If you have to mount half a mirror as read-write, then next time
you boot your normal config, unplug the second drive. Then power down,
plug it in, rebuild as usual.

Have fun,
Darren



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