Hello guys! Using Ubuntu which comes with grub 1.97~beta4:

root@voyager:~# grub-install /dev/sda7
grub-setup: warn: Attempting to install GRUB to a partition instead of the MBR. This is a BAD idea.
grub-setup: warn: Embedding is not possible. GRUB can only be installed in this setup by using blocklists. However, blocklists are UNRELIABLE and its use is discouraged.
Installation finished. No error reported.
This is the contents of the device map /boot/grub/device.map.
Check if this is correct or not. If any of the lines is incorrect,
fix it and re-run the script `grub-install'.

(hd0) /dev/sda

As you can see, the installation goes well, but, why installing grub into a partition instead of MBR is a bad idea?

I like to have many distros on my computer, and each one comes with their own menu.lst parameters, which also can change during updates. So it's much more pratical to create an empty partition of 64MB or less, create a /boot/grub there, install into MBR and then chainload into the other partitions.

So if I mess up with any distro, my mbr is still intact. And also if the parameters of grub setup required for a distro changes with any updates on the distro, they keep updated.

So for me it is not pratical to have one distro installed on MBR controlling the other ones, having to constantly change my menu.lst

But why does the program think it is not a good idea? What are the risks of installing GRUB into a partition instead of MBR? Why is this message displayed?

Thanks in advance for anyone who knows.

Edit: Maybe the question goes for why blocklists are unreliable or something like that?

Saikee is the grub master. Either this thread or this one should have your answers. If not post him a question.

Thanks DanceMan, I didn't find it on the threads put I'll PM him about this post.

Ubuntu uses GRUB2 as opposed to GRUB-legacy . There are some subtle and some not so subtle incompatibilities. Read e.g. this:

http://www.dedoimedo.com/computers/grub-2.html
http://ubuntuforums.org/printthread.php?t=1195275

I would guess that the program is simply saying: "putting GRUB on a partition is a bad idea if you don't know what you are doing." You obviously KNOW what you are doing, so worrying about this may not be necessary.....

I understand... actually the warning message that has made me doubt I was doing a good thing was "grub-setup: warn: Embedding is not possible. GRUB can only be installed in this setup by using blocklists. However, blocklists are UNRELIABLE and its use is discouraged." I have absolutely NO IDEA what it means but it *seemed* to be related to why installing GRUB in a root partition is a bad idea.

But if you say it may only be an "anti-newbie" warning, I believe.

Anyways, I didn't know that Ubuntu was using this still testing version of GRUB, that should explain the amout of weird files I've found on /boot/grub instead of just stage1, stage1_5, etc.

Thanks for the replies! =)

It's probably an "anti-newbie" warning.

I remember that the first time I tried installing Arch I installed GRUB in the root partition (thinking that's where it's supposed to be, I hardly know anything about bootloaders), and so the whole installation went for nothing.

Ok, I just hope we're right and I don't find the "hard way" that installing grub into a partition and not MBR could entirely corrupt that partition... lol

Thanks for the replies and the attention guys! =)

In case the subject is still of interest for you, here is a nifty way and explanation, when and why to place GRUB in the root partition: http://www.justlinux.com/forum/showthread.php?t=147959. Cheers.

As implied above, this is a grub2 issue only - not classic grub (aka grub1).
It is because of the structure of the core.img - this also requires a separate partition if gpt for similar reasons.

It is conceivably possible to screw up your boot if core.img gets moved at some point in the future. I've installed grub2 into the boot sector record several times without incident.
Your partition itself (and the data) is not in danger.

No it isn't. Specifically the OP asked "...why installing grub into a partition instead of MBR is a bad idea?" In answer of that I posted the above link.

The only problem I have had using grub2 in a separate partition to chainload is the device mapping of legacy distros. I have one IDE and one Sata drive. The Sata boots first, IDE second and grub 2 label them sda and sdb. For some reason three of the grub legacy list the device mapping is opposite. No problem to change, just a pain to find the problem the first time.

The OP asked the question badly. grub1 doesn't issue that (or similar) message, nor does it have any issue with being installed into the boot sector record.
This is a grub2 problem - only.

@syg00 Please clarify: Is this a problem of GRUB2 chainloading legacy GRUB? I don't use GRUB2 (yet) so I'm not familiar with "core.img" though I read up on it here: http://www.gnu.org/software/grub/man...de/Images.html. It is beyond me, though, why the developers chose a deployment which can be rendered unusable by the file system (again, if I understood correctly ).

I'm sorry, the question was not really "Why installing GRUB into a partition instead of MBR is a BAD idea?" but "Why did GRUB2 say that installing GRUB into a partition instead of MBR is a BAD idea?" As it seemed to be just an anti-newbie question only, I disregarded since the last of last year's replies and had no problem until now. Actually what most scared me was "Embedding is not possible. GRUB can only be installed in this setup by using blocklists. However, blocklists are UNRELIABLE and its use is discouraged" Hadn't and still haven't any idea about what it means, but this also seemed to give me no problem.

I also hadn't any problem about GRUB1 on MBR chainloading into GRUB2 and GRUB2 on MBR chainloading into GRUB1... =)