Bug#561294: core.img is unusually large, grub-pc fails to install grub mbr

[Thomas Fjellstrom]

On Fri December 18 2009, Felix Zielcke wrote:
> Am Donnerstag, den 17.12.2009, 14:30 -0700 schrieb Thomas Fjellstrom:
> > On Fri December 18 2009, Miguel Landaeta wrote:
> > > On Fri, Dec 18, 2009 at 4:08 PM, Thomas Fjellstrom
> >
> > <tfjellstrom at shaw.ca>
> >
> > wrote:
> > > > My core.img file is 31.13KB in size. Also the auto generated
> >
> > grub.conf
> >
> > > > seems to include a "raid" module that probably isn't needed? (it
> >
> > also
> >
> > > > includes mdraid and lvm) Is there a way I can remove it?
> > > >
> > > > And as I mentioned, I asked about this in the #grub channel on
> > > > irc.freenode.net and they seemed to hint at the fact that debian's
> >
> > grub
> >
> > > > package is known to make the driver modules larger in size that
> >
> > stock
> >
> > > > grub does.
> > >
> > > Ok, my core.img file was ~50KB so I had to repartition.
> > >
> > > In your case, you could use grub-mkimage to generate a new core.img,
> > >  remove some unused modules and see if you image can fit.
> >
> > I'm not sure how to do that. I've run grub-mkimage and overwrote
> > core.img
> > which gets me to a 20KB file, and grub-install overwrites it with a
> > larger
> > 31KB file. Changing grub.cfg is impossible as update-grub overwrites
> > that
> > every time. I can't see a reliable way of configuring grub2.
> 
> grub-install should only use the modules for core.img which are required
> to access /boot/grub.
> You can see the list with something like
> bash -x grub-install /dev/sda 2>&1 ¦ grep core.img
> 

unexpectedly, this is what I get from that:

# bash -x grub-install /dev/sdf 2>&1 ¦ grep core.img
+ transform=s,x,x,                                                                                                                 
+ prefix=/usr                                                                                                                      
+ exec_prefix=/usr                                                                                                                 
+ sbindir=/usr/sbin                                                                                                                
+ bindir=/usr/bin                                                                                                                  
+ libdir=/usr/lib                                                                                                                  
+ PACKAGE_NAME=GRUB                                                                                                                
+ PACKAGE_TARNAME=grub                                                                                                             
+ PACKAGE_VERSION=1.97+experimental                                                                                                
+ target_cpu=i386                                                                                                                  
+ platform=pc                                                                                                                      
+ font=/usr/share/grub/ascii.pf2                                                                                                   
++ echo grub/i386-pc                                                                                                               
++ sed s,x,x,                                                                                                                      
+ pkglibdir=/usr/lib/grub/i386-pc                                                                                                  
++ echo grub-setup                                                                                                                 
++ sed s,x,x,                                                                                                                      
+ grub_setup=/usr/sbin/grub-setup                                                                                                  
+ '[' i386-pc = i386-pc ']'                                                                                                        
++ echo grub-mkimage                                                                                                               
++ sed s,x,x,                                                                                                                      
+ grub_mkimage=/usr/bin/grub-mkimage                                                                                               
++ echo grub-mkdevicemap                                                                                                           
++ sed s,x,x,                                                                                                                      
+ grub_mkdevicemap=/usr/sbin/grub-mkdevicemap                                                                                      
++ echo grub-probe                                                                                                                 
++ sed s,x,x,                                                                                                                      
+ grub_probe=/usr/sbin/grub-probe                                                                                                  
++ echo grub-editenv                                                                                                               
++ sed s,x,x,                                                                                                                      
+ grub_editenv=/usr/bin/grub-editenv                                                                                               
+ rootdir=                                                                                                                         
++ echo /boot/grub
++ sed s,x,x,
+ grub_prefix=/boot/grub
+ modules=
+ install_device=
+ no_floppy=
+ force_lba=
+ recheck=no
+ debug=no
+ '[' i386-pc = i386-pc ']'
+ disk_module=biosdisk
+ for option in '"$@"'
+ case "$option" in
+ test x '!=' x
+ install_device=/dev/sdf
+ for option in '"$@"'
+ case "$option" in
+ test x/dev/sdf '!=' x
+ echo 'More than one install_devices?'
More than one install_devices?
+ usage
+ cat
Usage: grub-install [OPTION] install_device
Install GRUB on your drive.

  -h, --help              print this message and exit
  -v, --version           print the version information and exit
  --modules=MODULES       pre-load specified modules MODULES
  --root-directory=DIR    install GRUB images under the directory DIR
                          instead of the root directory
  --grub-setup=FILE       use FILE as grub-setup
  --grub-mkimage=FILE     use FILE as grub-mkimage
  --grub-mkdevicemap=FILE use FILE as grub-mkdevicemap
  --grub-probe=FILE       use FILE as grub-probe
  --no-floppy             do not probe any floppy drive
  --recheck               probe a device map even if it already exists
  --force                 install even if problems are detected
+ '[' i386-pc = i386-pc ']'
+ cat
  --disk-module=MODULE    disk module to use
+ '[' i386-pc = mips-yeeloong ']'
+ cat

INSTALL_DEVICE can be a GRUB device name or a system device filename.

grub-install copies GRUB images into the DIR/boot directory specified by
--root-directory, and uses grub-setup to install grub into the boot
sector.

Report bugs to <bug-grub at gnu.org>.
+ exit 1


Where as a plain:

# grub-install /dev/sdf

gives just:

/usr/sbin/grub-setup: warn: Your core.img is unusually large.  It won't fit 
in the embedding area.
/usr/sbin/grub-setup: error: Embedding is not possible, but this is required 
when the root device is on a RAID array or LVM volume.

What is making grub-install think it needs to print out the help message 
when run through bash -x ? And why isn't the 2>&1 working as it should?

-- 
Thomas Fjellstrom
tfjellstrom at shaw.ca