Bug#407338: Another GRUB upload

[Robert S. Edmonds]

On 2007-02-02, Steve Langasek <vorlon at debian.org> wrote:
> On Fri, Jan 26, 2007 at 09:05:06AM -0200, Otavio Salvador wrote:
>> I've received a bug report[1] with an interesting patch on GRUB. This
>> patch adds support to GPT on it.
>
>> 1. http://bugs.debian.org/407338
>
>> That would be great since it makes the Appled based Intel machines
>> much simple to install and since the patch isn't too invasive I would
>> like to get it in.
>
>> Please check the bug report and post your complains ;-)

I have also run into this bug independently on several storage servers
with >2 TB of space recently.  I applied Marco Gerards' patch[0] to the
grub 0.97-22 package (it applied cleanly) and built a "grub-gpt"[1]
package.  This patch worked for me with a GPT partition table on i386
and amd64.  Using the etch rc1 installer, simply chrooting into /target
and installing this patched package, running update-grub and
grub-install and selecting "continue without a boot loader" were
sufficient to boot a newly installed system successfully.

Marco notes in [0] that his patch will not be included in grub 'legacy',
as upstream is in feature freeze; the last release was made nearly two
years ago.  However, he adds "but I hope this will be useful for at
least some people or distributions."

Other workarounds for the lack of GPT support include connecting a small
IDE flash module to the motherboard for the /boot filesystem, a
technique I employed up until today when I ran out of them; placing
another disk in the system for /boot, which unfortunately wouldn't be
protected from failure by RAID; enabling "LUN carving" if your
controller supports it, which has additional downsides (e.g., employing 
LVM to stitch the space back together).

> The bug report claims:
>
>> GRUB is currently the only bootloader which is able to
>> boot from GPT partitions which are mandatory when partitioning
>> blockdevices which exceed 2TB in size (and become more and more common
>> due to the latest developments in the storage sector).
>
> Isn't elilo also able to boot from GPT partitions?

Description: Bootloader for systems using EFI-based firmware
 This is the Linux bootloader for systems using the Intel EFI firmware
 specification.  This includes all ia64 systems, and some ia32 systems.

elilo is not available on the amd64 platform, and furthermore a grub
which supports gpt is useful even on systems with a conventional non-EFI
BIOS.  4-port and 8-port RAID controllers are commonly available which
can be used on these platforms to create >2 TB RAID devices with 750 GB
or 500 GB SATA drives.  It is important to note that the use of GPT is
not limited to EFI hardware.  GPT can provide benefits over msdos
partition tables on standard i386/amd64 hardware.

partman will automatically select the gpt table format if a block device
larger than 2 TB is partitioned, but if /boot is on this block device
grub cannot be installed.

I am unsure if the standard lilo in etch can boot off these devices, but
lilo is an enormous backwards step in features from grub.  Robert Millan
suggests the use of grub2 in #407338, but it seems this package is
marked "[EXPERIMENTAL]" in the short description and is not available in
testing.

[0] http://www.mail-archive.com/bug-grub@gnu.org/msg10632.html
[1] http://debian.gtisc.gatech.edu/packages/grub-gpt/grub_0.97-22~rse0.dsc

-- 
Robert Edmonds
edmonds at debian.org
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