[clug] Grub trouble

Sam Couter sam at couter.id.au
Wed Sep 20 09:28:14 GMT 2006

Mike Carden <mike.carden at gmail.com> wrote:
> A screen full of GRUB GRUB GRUB GRUB GRUB GRUB GRUB GRUB. And nothing else.

When you restore the disk image, the GRUB second-stage loader has to
arrive on the exact same disk block that the MBR thinks it was on.

The first-stage GRUB loader can't read filesystems, it just knows
blocks. Like LILO. The second stage loader is loaded directly from a
range of disk blocks. This range is stored in the MBR. The second stage
loader is the one that can find arbitrary files and such on the
filesystem, unlike LILO. Where LILO is affected by new kernels being
installed on different disk blocks, GRUB is affected by the second stage
loader moving around on disk.

So if your image restoration puts the second stage loader on the same
disk block every time, run install-grub just once on each machine from a
rescue disk to update the MBR with that block.

If the restoration might put the second stage loader on a different disk
block each time, you're going to have to run install-grub every time you
restore, or just always boot from rescue media.
Sam Couter         |  mailto:sam at couter.id.au
                   |  jabber:sam at teknohaus.dyndns.org
OpenPGP fingerprint:  A46B 9BB5 3148 7BEA 1F05  5BD5 8530 03AE DE89 C75C
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 189 bytes
Desc: Digital signature
Url : http://lists.samba.org/archive/linux/attachments/20060920/d09f308e/attachment.bin

More information about the linux mailing list