Re: Embedding core.img in an empty partition

[Chris Murphy]

On Aug 1, 2012, at 5:37 PM, Damien Robert wrote:

> (Sorry for breaking the thread, but I did not receive the reply, I copied
> it from the web-archive).
> 
>> Sounds less painful to move/resize the file system starting at sector 63.
>> What file system is it?
> 
> This is an lvm file system,containing my / and /home lvm partitions. So
> moving it would require to do it from a live cd

Add a disk, use pvmove, remove the disk from the group, repartition the 
original disk, readd it to the group, pvmove extents back. Can be done live. 
Faster than dd.

>> If you use the force flag with grub-install, it will find  the space at the
>> end of the disk and use it (block lists).
> 
> I thought that the --force flag use as block lists the blocks where the
> core.img reside in the /boot partition (so in my case ext4 inside lvm). So
> that any change in the /boot filesystem could break the block list.

No. It uses unallocated space. That's why it's fragile, because other things 
could also use unallocated space (although they tend not to).

Embedding in partitions has various problems. GRUB2 documentation doesn't 
outright proscribe doing it, but I think it's fair to say it's not advised.


> Are you saying that instead  the force --flag still copy the core.img file,
> but embed it into several empty spaces?

That's what I was thinking, but when I read the GRUB2 manual, I can't tell what 
--force actually does. However on Fedora forums, many users have used 
grub-install --force when getting the error that core.img is too big when 
otherwise invoking grub-install without --force. I was just assuming it was 
creating its own block list, because it did end up fixing the problem.

--no-floppy might also make core.img small enough to embed.


Chris Murphy