Peter Olson <peabo@???> wrote:

> My principal complaint about GRUB is that it works very well until one day
> when it doesn't, when it now provides the minimal help conceivable to boot
> your machine.

INdeed, and IMO the use of UIDs is something of a PITA - great for working around the "devices enumerate differently" problem, but a real PITA when manual intervention is needed. AIUI Grub also supports filesystem labels - but the Debian setup doesn't include that option.

But, I had a problem last week, and got pointed to http://www.supergrubdisk.org
Grab it, burn it to disk (or USB device), and most of the work is dealt with. One keypress to load raid and LVM, another to get it to search the system for booting options - pick and option, and "tada". Once booted you can fix the bootloader.

Didn't actually deal with my problem last week though, which was a recalcitrant HP Microserver which (after I removed a failed disk - I hate Seagate even more now) would give me nothing but a blank screen with a flashing underscore to taunt me.. After several days, the penny dropped - this is one of those systems where you can specify the disk to boot from - and after I took the failed disk out, it then tried to boot from a non-bootable disk.

> several years ago involved a problem where a RAID 1 device
> was enumerated differently, but more recently I have had problems with trying
> to boot a supposedly exact restored copy of a system on a different disk.

In both those situations I'd boot from a live disk (since nearly everything I run is Debian, this would be either a Debian live disk or the Rescue option of an installer disk). It just has to be "similar" to the installed system ..

mount /dev/... /mnt
mount /dev/... /mnt/boot
and so on ...
mount -o bind /proc /mnt/proc
mount -o bind /sys /mnt/sys
mount -o bind /dev /mnt/dev
chroot /mnt
update-grub
grub-install /dev/...

This has fixed things for me on no end of occasions - at one time I had to look it up, now the sad geek in me doesn't have to :-/


But didn't LILO have similar (or worse) problems ? It's a long time since I've used it, but didn't break any time up updated anything - and you had to remember to re-install it so it could update the block list (because it just had a list of blocks, it didn't understand filesystems) for loading the initial image ? Or something like that ?