[SOLVED] [LFS 7.3} 8.4 GRUB Install

DeeGee · 05-07-2013, 12:14 AM

Phew, I've come a long way up this steep learning curve!

Need some help with the final step. Am a bit confused by the book's instructions regarding the code.

I don't have a separate boot partition and have decided to install grub in root(sda3). So the process should be as follows: Please clarify me.

Code:

$ cd /boot/grub
$ grub-install /dev/sda3

Lennie · 05-07-2013, 01:25 AM

If you don't have another bootloader that you use with chainloading, you should install grub in mbr (sda).

You don't need to cd to your grub-folder to install grub in mbr. You can run 'grub-install /dev/sda' from anywhere.

DeeGee · 05-07-2013, 03:01 AM

Quote:

Originally Posted by Lennie

If you don't have another bootloader that you use with chainloading, you should install grub in mbr (sda).

You don't need to cd to your grub-folder to install grub in mbr. You can run 'grub-install /dev/sda' from anywhere.

Just to clarify, I install the qrub as the same location as as that of the host?

druuna · 05-07-2013, 03:19 AM

Quote:

Originally Posted by DeeGee

Just to clarify, I install the qrub as the same location as as that of the host?

When you reach the grub chapter you basically have 2 choices to consider:

1) Use the bootloader that your host has set up and add an entry for LFS. If you decide to do this then you can skip the grub chapters mentioned in the LFS book.

You do need to add an entry to Debian's grub configuration (run update-grub2 on your Debian box). You'll end up with a dual boot system (Debian and lfs in your case).

2) Install and configure grub as described by the LFS book.
This does have a possible down side: Debian's grub will be overwritten and become useless. If, on the other hand, Debian is only used as a temporary host (Debian will be removed once LFS is up and running) then you will have to build and configure grub as shown in the LFS book.

The configuration needs to be tailored to your needs/setup, you cannot just copy the current settings used by Debian.

DeeGee · 05-07-2013, 04:14 AM

Quote:

Originally Posted by druuna

2) Install and configure grub as described by the LFS book.
This does have a possible down side: Debian's grub will be overwritten and become useless. If, on the other hand, Debian is only used as a temporary host (Debian will be removed once LFS is up and running) then you will have to build and configure grub as shown in the LFS book.

The configuration needs to be tailored to your needs/setup, you cannot just copy the current settings used by Debian.

I wish to go by this option. So, shall I go on by installing grub to sda (or should it be sda1)?

Thank you for the very clear explanation

.

druuna · 05-07-2013, 04:23 AM

Quote:

Originally Posted by DeeGee

I wish to go by this option. So, shall I go on by installing grub to sda (or should it be sda1)?

Thank you for the very clear explanation

.

It should be installed to the MBR (disk) and not a partition.

If the disk is assigned to sda then you need to use grub-install /dev/sda.

You did mention this being done inside a VM, this might indicate that the disk assignment might be different (vda for example). Run df -h or fdisk -l on your Debian host to show what's being used. This info might also be handy for the construction of the /boot/grub/grub.cfg file.

DeeGee · 05-07-2013, 04:56 AM

Code:

Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1         973     7811072   83  Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2             973        1066      748545    5  Extended
/dev/sda3            1066        2610    12403161   83  Linux
/dev/sda5             973        1066      748544   82  Linux swap / Solaris

This is my partitioning scheme, so accordingly there's no problem and can use sda straightaway, I believe.

Also, for the grub.cfg file I'm a bit confused about some parts and their meanings.

Code:

cat > /boot/grub/grub.cfg << "EOF"
# Begin /boot/grub/grub.cfg
set default=0
set timeout=5
insmod ext2
set root=(hd0,2)
menuentry "GNU/Linux, Linux 3.8.1-lfs-7.3" {
        linux    /boot/vmlinuz-3.8.1-lfs-7.3 root=/dev/sda3 ro
}
EOF

As my LFS partition is sda3, I've modified the file accordingly. My problem is with the set root value. Is the current value correct?

druuna · 05-07-2013, 05:13 AM

You need to follow the Grub naming convention (mentioned in the book) to set the root=(hdX,Y) option:

Code:

sda1 -> hd0,1
sda2 -> hd0,2
sda3 -> hd0,3
sdb1 -> hd1,1
sdb2 -> hd1,2
etc...

LFS is using /dev/sda3 and I do not see a separate /boot partition:

Code:

cat > /boot/grub/grub.cfg << "EOF"
# Begin /boot/grub/grub.cfg
set default=0
set timeout=5
insmod ext2
set root=(hd0,3)
menuentry "GNU/Linux, Linux 3.8.1-lfs-7.3" {
        linux    /boot/vmlinuz-3.8.1-lfs-7.3 root=/dev/sda3 ro
}
EOF