[TriLUG] Need Grub help

Wed May 2 07:43:56 EDT 2018

If you are using rescue CD you will have to mount your drives and chroot
into your root dirs for this. The commands I gave will work when you are
already in the system. But chroot should work.

On Wed, May 2, 2018, 7:41 AM vikram sai balaji ulaganathan <
tayirvadai.vikram at gmail.com> wrote:

> Typically I do the following. Note that I only have 1 hard drive /dev/sda
> with efi, swap, boot, root and home partitions
> 1. Grub-mkconfig -o grub.cfg
> 2. As root copy grub.cfg to /boot/grub/
> 3. Make sure /etc/fstab has the right partition entries
> 4. Assuming efi partition was formatted as vfat and firmware installed
> already and mounted on /boot/efi I use
> grub-install --efi-directory=/boot/efi
> 5 Reboot
>
> I do this in Gentoo which has the steps. Ignoring the emerge commands
> these steps should work. This is just how mine is setup. Yours may need
> additional parameters. Always backup before you try any commands.
>
> On Tue, May 1, 2018, 8:44 PM Paul Boyle via TriLUG <trilug at trilug.org>
> wrote:
>
>> Thanks for the link Scott.
>>
>> I got up to the part where it says to run grub2-install.  That failed,
>> not surprisingly because this is an EFI system.  I followed the directions
>> farther down regarding grub2-mkconfig.  I saw that the program found my
>> kernel and initrd images.  When I tried to reboot it didn't work.  I found
>> this page:
>>
>> https://fedoraproject.org/wiki/GRUB_2
>>
>> The bottom line from that page was don't use grub2-install on EFI
>> systems.  There doesn't seem to be an analogous program for EFI system.  I
>> tried a couple of time running grub2-config.  It could find the images, but
>> couldn't boot.
>>
>> I guess this will have to wait until I get back from vacation.  Thanks
>> for your help.
>>
>> Paul
>>
>> ________________________________________
>> From: Scott Lambdin <lopaki at gmail.com>
>> Sent: May 1, 2018 7:11 PM
>> To: Paul Boyle; Triangle Linux Users Group General Discussion
>> Subject: Re: [TriLUG] Need Grub help
>>
>> Hi -
>>
>> I think this looks pretty good for you:
>>
>> https://www.thegeekdiary.com/centos-rhel-7-how-to-reinstall-grub2-from-rescue-mode/
>>
>> --Scott
>>
>> On Tue, May 1, 2018 at 6:02 PM, Paul Boyle via TriLUG <trilug at trilug.org
>> <mailto:trilug at trilug.org>> wrote:
>> Hi,
>>
>> I had the hard drive which contains the OS and distro (CENTOS 7) on one
>> of my student workstations fail (a hardware failure). /home is on a
>> separate drive which is OK. I was able to clone the image of the drive
>> to another hard drive (partitions look OK from gdisk). The cloned
>> partitions can be mounted via a harness on another Linux box.
>>
>> The layout of the disk is:
>> /dev/sda1 -> /boot/efi (msdos(?))
>> /dev/sda2 -> /boot (ext4)
>> /dev/sda3 -> / (ext4)
>> /dev/sda4 -> Linux swap
>>
>> I put the cloned drive into the PC. and when I try to boot I get an
>> error saying
>>
>> "Reboot and select proper boot device
>> or Insert Boot media into selected boot device and press a key".
>>
>> I'm thinking I need to run GRUB2 to make the system boot from new hard
>> drive.  However, I am befuddled by GRUB2.  Can someone suggest a
>> sensible course of action?
>>
>> I'm thinking  putting a original CENTOS install DVD and
>> choosing the rescue option.  However, I don't know really what to do
>> after that.
>>
>> Any help appreciated.
>>
>> Reason to break out the world's smallest violins:  I'm scheduled to
>> start my vacation tomorrow and I would love to get this sorted out this
>> evening.
>>
>> Thanks,
>>
>> Paul
>>
>> --
>> Paul D. Boyle, Ph. D.
>> Manager, X-ray Facility
>> Department of Chemistry
>> Western University
>> London, ON N6A 5B7
>> Canada
>> GPG Fingerprint: 8ECE 516D 9046 FE83 4A46  7E8E D720 555D 8CC3 EC6B
>>
>> --
>> This message was sent to: Scott Lambdin <lopaki at gmail.com<mailto:
>> lopaki at gmail.com>>
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>>
>>
>>
>> --
>>
>> Eat like you give a damn.  Go vegan.
>> --
>> This message was sent to: Vikram <tayirvadai.vikram at gmail.com>
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>> that address.
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>
>