[solved] gentoo on /dev/sdc

seneca · n00b Joined: 10 Apr 2013 Posts: 53

Any thoughts on the correct grub2 entry for this scenario:

1. PC with three hard drives, sda (contains debian wheezy), sdb (contains backups, etc), sdc (has gentoo)
2. The sdc with gentoo was on a different PC originally, where it was sda and installed with sda1=boot, sda2=swap, sda3=root

If I run 'update-grub' from sda (debian), the gentoo is noted but grub's menu does not update to include gentoo. If I manually make an entry in debian's grub.d/40_custom, gentoo starts to boot but fails to find 'sda3' to mount root. Changing the grub entry for gentoo to 'sdc3' or adding a dalay of 30 seconds does not fix the issue.

So, how would one write the entry to have gentoo boot?
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Whatever is well said by another, is mine.
I don't consider myself bald, I'm just taller than my hair.

Lucius Annaeus Seneca

genterminl · Posted: Mon Sep 02, 2013 10:51 pm Post subject:

What part of the boot sequence is failing to find "sda3" ? If it's something within the kernel (like an initram) then you need to fix that to point to sdc3. However, unless you can fix it with sda3 mounted from debian, you might need to make that drive sda, boot gentoo, fix it so it looks for sdc, then switch the drives back. I don't know grub2 well enough, but it might help for you to post what you've tried so far, and also post the grub entry from the gentoo drive.

quilosaq · Veteran Joined: 22 Dec 2009 Posts: 1522

Maybe you must update /etc/fstab in gentoo root filesystem:

ryo-san · l33t Joined: 17 Feb 2005 Posts: 729

hi

seneca · n00b Joined: 10 Apr 2013 Posts: 53

Hi guys. Thanks for taking the time to help.

I am writing from my laptop as the PC wont boot at all after all the "experiments".... I am going to reinstall all from scratch this weekend. Any advice to supplement the information on the gentoo site installation pages on how to modify the installation instructions when installing gentoo on a drive other than the sda (in my case, gentoo will go on sdc)? Things like: should I install grub only on sda (where debian will go) or should I install grub on sda AND sdc, then chainload the sdc grub from sda, or, "keep it simple until you learn more and install all of gentoo on a single partition" (no separate partition for boot), etc

You have the right to ask: why the hell are you installing both gentoo and Debian? well... I am trying to learn linux and the use of both is supplemental as a learning experience, with gentoo the harder of the two but also the more fun to work with.

Any guidance will be very much appreciated
_________________
Whatever is well said by another, is mine.
I don't consider myself bald, I'm just taller than my hair.

Lucius Annaeus Seneca

genterminl · Posted: Tue Sep 03, 2013 1:24 pm Post subject:

Your setup is simple enough that it really should work without too much effort. Personally, I would only install grub (grub or grub2? either is good, but they are rather differeent) on sda. The only issue I see is when you do the second install (either order, Gentoo or Debian) I don't know if the installer will correctly add the new OS to the existing grub or if you will need to make the addition manually.

One additional thing you might try is booting from a rescue disk or live cd (or even usb stick if the box will boot from usb). That way, you can make changes to the existing setup and try again without a full reinstall.

However, for any better ideas on what went wrong, you need to post more details about your setup and error messages.

Good luck and keep learning.

Jack

cwr · Veteran Joined: 17 Dec 2005 Posts: 1969

I always put grub on sda (on its own partition) but once I've installed grub
it will boot any partition on sda/b/c/d/e, with the appropriate editing of grub.conf
The trouble is that I use grub 1.x, so I can't tell you how to set up grub 2.x
However, it should be pretty straightforward.

The boot process is MBR => grub => kernel, so the MBR has either to find
the grub partition directly, or boot through a windows menu (often helpful
in dual-booting systems) to find grub. But once grub's running it's easy.

Will

seneca · n00b Joined: 10 Apr 2013 Posts: 53

Thanks guys

The rescue CD is a good idea but I think I will reinstall all again to get rid of all the manual changes I made trying to get that to work...I lost track of all the changes, which is the first rule I violated with this: keep a log.

I will do the install of grub on sda only, as well advised, and will do 'grub-update' from there once I get sdc installed.

Again, thanking you all, I will mark this as solved.
best
_________________
Whatever is well said by another, is mine.
I don't consider myself bald, I'm just taller than my hair.

Lucius Annaeus Seneca

seneca · n00b Joined: 10 Apr 2013 Posts: 53

just a follow-up

I installed as before but this time with grub only on sda (with the Debian) and with gentoo on sdc1 (no separate /boot partition) and it works great.

best to all
_________________
Whatever is well said by another, is mine.
I don't consider myself bald, I'm just taller than my hair.

Lucius Annaeus Seneca