Grub reinstall doesnt generate grub.cfg

[siddhartpai]

I have ubuntu 10.10 running on my HP dv5 pavilion laptop
So today i tried to reinstall grub on my pc ..
i removed grub-pc and grub-common using synaptic
then booted up with a live cd of ubuntu 10.04
i then mounted sda11 to mnt
using
sudo mount /dev/sda11 /mnt
sda11 being my ubuntu directory containing the /boot
then i installed grub to it
using
sudo grub-install --root-directory=/mnt /dev/sda
it reported as installation finished.No error reported
then i unmounted /mnt
and checked for /boot/grub/grub.cfg
seems like the file is missing
so are the files in /etc/grub.d/
so please help me to reinstall my grub back

[siddhartpai]

Boot Info Script 0.55 dated February 15th, 2010

============================= Boot Info Summary: ==============================

=> Grub 2 is installed in the MBR of /dev/sda and looks on the same drive in
partition #11 for /boot/grub.

sda1: __________________________________________________ _______________________

File system: ntfs
Boot sector type: Windows Vista/7
Boot sector info: No errors found in the Boot Parameter Block.
Operating System:
Boot files/dirs: /bootmgr /Boot/BCD /grldr

sda2: __________________________________________________ _______________________

File system: Extended Partition
Boot sector type: -
Boot sector info:

sda5: __________________________________________________ _______________________

File system: ntfs
Boot sector type: Windows Vista/7
Boot sector info: According to the info in the boot sector, sda5 starts
at sector 2048.
Operating System:
Boot files/dirs:

sda6: __________________________________________________ _______________________

File system: ntfs
Boot sector type: Windows Vista/7
Boot sector info: According to the info in the boot sector, sda6 starts
at sector 2048.
Operating System:
Boot files/dirs:

sda7: __________________________________________________ _______________________

File system: ntfs
Boot sector type: Windows Vista/7
Boot sector info: According to the info in the boot sector, sda7 starts
at sector 2048.
Operating System: Windows 7
Boot files/dirs: /Windows/System32/winload.exe

sda8: __________________________________________________ _______________________

File system: ntfs
Boot sector type: Windows Vista/7
Boot sector info: According to the info in the boot sector, sda8 starts
at sector 2048.
Operating System:
Boot files/dirs:

sda9: __________________________________________________ _______________________

File system: ntfs
Boot sector type: Windows Vista/7
Boot sector info: According to the info in the boot sector, sda9 starts
at sector 2048.
Operating System:
Boot files/dirs:

sda10: __________________________________________________ _______________________

File system: swap
Boot sector type: -
Boot sector info:

sda11: __________________________________________________ _______________________

File system: ext4
Boot sector type: -
Boot sector info:
Operating System: Ubuntu 10.10
Boot files/dirs: /etc/fstab /boot/grub/core.img

sda12: __________________________________________________ _______________________

File system: ext4
Boot sector type: -
Boot sector info:
Operating System:
Boot files/dirs:

=========================== Drive/Partition Info: =============================

Drive: sda ___________________ __________________________________________________ ___

Disk /dev/sda: 250.1 GB, 250059350016 bytes
255 heads, 63 sectors/track, 30401 cylinders, total 488397168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes

Partition Boot Start End Size Id System

/dev/sda1 * 2,048 206,847 204,800 7 HPFS/NTFS
/dev/sda2 208,894 488,394,751 488,185,858 5 Extended
/dev/sda5 28,209,152 128,206,847 99,997,696 7 HPFS/NTFS
/dev/sda6 128,208,896 228,206,591 99,997,696 7 HPFS/NTFS
/dev/sda7 228,208,640 268,206,079 39,997,440 7 HPFS/NTFS
/dev/sda8 268,208,128 368,205,823 99,997,696 7 HPFS/NTFS
/dev/sda9 368,207,872 488,394,751 120,186,880 7 HPFS/NTFS
/dev/sda10 26,193,920 28,194,815 2,000,896 82 Linux swap / Solaris
/dev/sda11 208,896 24,240,127 24,031,232 83 Linux
/dev/sda12 24,242,176 26,185,727 1,943,552 83 Linux


blkid -c /dev/null: __________________________________________________ __________

Device UUID TYPE LABEL

/dev/loop0 squashfs
/dev/sda10 87e12758-e604-4232-990d-58f3590d0a61 swap
/dev/sda11 948dea34-8d15-43fd-9694-4914384351c9 ext4
/dev/sda1 2A223A74223A44DB ntfs System Reserved
/dev/sda12 db534f61-cb92-4c19-99c1-d3a60b47b7f4 ext4
/dev/sda2: PTTYPE="dos"
/dev/sda5 0E5A1C565A1C3D41 ntfs Soft Stuff
/dev/sda6 F4CC5D0CCC5CCB0E ntfs Chill
/dev/sda7 8C5E2DC65E2DA9C2 ntfs *******
/dev/sda8 2CE637D7E6379FCE ntfs Miscellaneous
/dev/sda9 1E02C26C02C2490B ntfs Music
/dev/sda: PTTYPE="dos"
error: /dev/sdb: No medium found

============================ "mount | grep ^/dev output: ===========================

Device Mount_Point Type Options

aufs / aufs (rw)
/dev/sr0 /cdrom iso9660 (ro,noatime)
/dev/loop0 /rofs squashfs (ro,noatime)
/dev/sda8 /media/Miscellaneous fuseblk (rw,nosuid,nodev,allow_other,blksize=4096,default_ permissions)
/dev/sda11 /media/948dea34-8d15-43fd-9694-4914384351c9 ext4 (rw,nosuid,nodev,uhelper=udisks)
/dev/sda11 /mnt ext4 (rw)


=============================== sda11/etc/fstab: ===============================

# /etc/fstab: static file system information.
#
# Use 'blkid -o value -s UUID' to print the universally unique identifier
# for a device; this may be used with UUID= as a more robust way to name
# devices that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point> <type> <options> <dump> <pass>
proc /proc proc nodev,noexec,nosuid 0 0
/dev/sda11 / ext4 errors=remount-ro 0 1
/dev/sda10 none swap sw 0 0

=================== sda11: Location of files loaded by Grub: ===================


6.8GB: boot/grub/core.img
3.6GB: boot/initrd.img-2.6.35-22-generic
4.4GB: boot/initrd.img-2.6.35-23-generic
6.8GB: boot/vmlinuz-2.6.35-22-generic
6.9GB: boot/vmlinuz-2.6.35-23-generic
4.4GB: initrd.img
3.6GB: initrd.img.old
6.9GB: vmlinuz
6.8GB: vmlinuz.old
=======Devices which don't seem to have a corresponding hard drive==============

sdb

[Rubi1200]

Hi and welcome to the forums :)

As you suspected, you are definitely missing files.

The best way to deal with this is to purge and reinstall GRUB from the LiveCD.

The following fantastic guide by drs305 uses the chroot method to accomplish this task:
http://ubuntuforums.org/showthread.php?t=1581099

You must use the chroot method, mount sda11, and install GRUB to the MBR.

Good luck and let us know what happens.

[siddhartpai]

I solved it myself by using the chroot procedure..
http://ubuntuforums.org/showthread.php?t=1581099
Thanks Everybody
To Admin Please Close the Topic

[Quackers]

siddhartpai, it's you that can mark the thread as solved using the thread tools near the top of the page :-)

[Herman]

:D Hmmm, interesting thread!

So you learned that when GRUB is installed, (as part of the operating system), it consists not only of the obvious files in /boot/grub that everyone knows about, but is also made up of important files in /etc, /usr/bin, usr/lib and usr/share.
If you want to see the complete list you can open Synaptic Package Manager and search for 'grub-pc', then look in the 'installed files' tab there.
When you completely remove GRUB with Synaptic Package Manager, it removes all of the GRUB files from the whole operating system, so you lose all the commands associated with GRUB like grub-install and grub-mkconfig too.

The grub-install command you used from the Live CD creates the /boot/grub directory and fills it up with GRUB files, all except for the grub.cfg.
A different command is needed to create the /boot/grub/grub.cfg file, either grub-mkconfig or update-grub (which is just another name for grub-mkconfig, but easier for new users to remember).
The grub-install command doesn't install all the other GRUB files in the operating system such as in /etc and /usr though, you need to use apt-get or synaptic to install the entire grub-pc package, so that's why you needed to chroot.

I imagine explaining this will seem like 'overkill' for some of us, but the extra explanation might be of some benefit to new users who may be wondering what's going on here. :)

[Quackers]

I have to admit to be somewhat confused by this.
I would have put the lack of /boot/grub/grub.cfg down to an installation error (not knowing any better :-) ). Otherwise how would the chroot method be any different? It still installs grub to the mbr of the drive and the grub files to sda11 (in this case) by mounting that partition first.
Am I missing a link here?

[Herman]

Okay, I'll explain what I think happened.

First, the OP used Synaptic Package Manager to remove the grub-pc package,

I have ubuntu 10.10 running on my HP dv5 pavilion laptop
So today i tried to reinstall grub on my pc ..
i removed grub-pc and grub-common using synapticNow, if you tak a look in your own Synaptic Package manager and search 'grub-pc', then right-click on the grub-pc line and click 'properties', and go to the 'installed files' tab you can see all the files in the grub-pc package and where they are placed in the file system.

Now, if you go take a look at some of those files, you be able to see which ones the OP says were removed, and the list includes scripts and programs associated with GRUB, such as /usr/sbin/grub-install, /usr/sbin/grub-reboot, /usr/sbin/grub-set-default, /usr/sbin/grub-setup, /usr/sbin/update-grub, /usr/bin/grub-mkimage and so on.

Okay, so at this point it's no use trying to run grub-install or any other command from within the operating system because all of those programs have been removed, they're gone.

Re-installing GRUB with Synaptic Package Manager or apt-get would have fixed it though, because that would have put all those programs that are part of the grub-pc package back where they belong again.

Instead, the OP chose to reboot, and re-install grub from a Live CD.
That only installs the files in /boot/grub, plus installs GRUB to MBR.
It doesn't re-install any of the GRUB files from the grub-pc package that live deeper inside the operating system.

then booted up with a live cd of ubuntu 10.04
i then mounted sda11 to mnt
using
sudo mount /dev/sda11 /mnt
sda11 being my ubuntu directory containing the /boot
then i installed grub to it
using
sudo grub-install --root-directory=/mnt /dev/sda
it reported as installation finished.No error reported
then i unmounted /mnt
and checked for /boot/grub/grub.cfg
seems like the file is missing
so are the files in /etc/grub.d/
so please help me to reinstall my grub back The grub-install command never did make a grub.cfg file either, we need to use grub-mkconfig separately for that.
(As a little irrelevant info on the side, most people say they use 'update-grub', but that only runs a script that runs 'grub-mkconfig', so they're still using grub-mkconfig but they don't know it.)

So correctly, Rubi1200 advised:

The best way to deal with this is to purge and reinstall GRUB from the LiveCD. ... and if you read fantastic guide by drs305 about using the chroot method to accomplish this task: http://ubuntuforums.org/showthread.php?t=1581099, you will see in step 3 where it explains how to purge grub packages and in step 4 where drs305 demonstrates re-installing grub with an apt-get command.
So in other words all the scripts and programs normally associated with GRUB that live elsewhere in the operating system are now replaced, not just the grub files in /boot/grub.

The files in /boot/grub are all that are required to boot the operating system, providing you have a grub.cfg unless you can use GRUB's command line. To run update-grub or grub-mkconfig we need all those other programs that come with the grub-pc package.

Sabbe? :)

[Quackers]

Thank you for your detailed response Herman :-)

I am somewhat familiar with drs305's excellent guide(s) :-)
In fact the purge/re-install grub is my most used link ;)

[drs305]

Herman's analysis is, as usual, spot on.

Since this thread is going into some detail on this, I'll add the reason to purge/install rather than just a "--reinstall". For whatever reason, if a user intentionally or unintentionally deletes or renames a file, the system remembers that action. On a reinstall, APT will restore missing packages if they were not removed or renamed (by root). So if Grub 2 is failing because the user removed/renamed a file, a simple reinstall will not normally replace the manually-removed file and the package will remain broken.

If the entire package is removed (purged), all the files are installed and the package should be returned to working order. Since in many cases we may not know the reason the files are missing or corrupted, purging first offers the highest likelihood the action will succeed.

[Herman]

:p Cool! Thanks for taking the time to explain that, drs305, now it was my turn to learn something, thank you for sharing.

and thank you too, Quackers, for your excellent question. :)

[Quackers]

I have this hunger to know things :-) Particularly about grub2.