Error on Boot: could not find root block device

aspasia · n00b Joined: 22 Apr 2008 Posts: 24

Hello all,

I have reviewed all prior posts related to or with similar symptoms as I experienced whereupon after installing using the MinimalCD, stage3tar and manually compiling the kernel (while following the suggestions on enabling my SATA-related modules in make menuconfig), after many attempts and permutations, I am still getting the same errors of:

VFS: Cannot open root device "sda2" or unknown block (0,0) Please append a correct root=boot option.

grub.conf is per Gentoo handbook'srecommendation:
----------------------------------------------------------------
default 0
timeout 30
splashimage=(hd0,0)/boot/grub/splash.xpm.gz
title Gentoo Linux 2.6.24-r4
root (hd0,1)
kernel /boot/kernel-2.6.24-gentoo-r4 root=/dev/sda2

also manually installed grub:

grub> root (hd0,0)
root (hd0,0)
Filesystem type is ext2fs, partition type 0x83
grub> setup (hd0)
setup (hd0)
Checking if "/boot/grub/stage1" exists... yes
Checking if "/boot/grub/stage2" exists... yes
Checking if "/boot/grub/e2fs_stage1_5" exists... yes
Running "embed /boot/grub/e2fs_stage1_5 (hd0)"... 16 sectors are embedded.
succeeded
Running "install /boot/grub/stage1 (hd0) (hd0)1+16 p (hd0,0)/boot/grub/stage2 /boot/grub/menu.lst"... succeeded
Done.
grub> quit
============

My question: Is there an ISO/DVD installer version that I can just simply download and run install just like CentOS, Fedora and the likes - where I do not have to download source, make kernel changes and compile? I would love to further play with this, but am on a time crunch ....

My understanding (I am a noob) is that Gentoo installs requires compiling, is this correct? If I am wrong, can you pls let me know what DVD/iso I can download that would allow me to easily install the distribution without compiling?

I will try to revisit this after completing a couple of other projects, but if someone can bounce off a couple of two cents, would be greatly appreciated!

Best,

Aspasia.

aspasia · n00b Joined: 22 Apr 2008 Posts: 24

just to clarify - typo on my cut n paste of the grub.conf -- root(hd0,0)

default 0
timeout 30
splashimage=(hd0,0)/boot/grub/splash.xpm.gz
title Gentoo Linux 2.6.24-r4
root (hd0,0)
kernel /boot/kernel-2.6.24-gentoo-r4 root=/dev/sda2

thx!

- A.

dageyra · Posted: Wed Apr 23, 2008 6:24 pm Post subject:

Did you compile the drivers for you hard drives in as modules or directly into the kernel? I use Lilo myself, so I'm not sure about your Grub config, but when I got these messages, it was because I just had forgotten to run lilo to update the boot partition or because I didn't have the write drivers compiled directly into the kernel (module loading does't work because the modules aren't loaded until after boot). Also, you should ensure only the drivers needed are compiled in because I've experienced issue where drivers conflicted with one another.

I use Gentoo because it allows me to have a system optimized and tweaked without a lot of compiling knowledge, this is why Gentoo uses source compiling. I think the Gentoo kernel could probably help you, I don't remember what they are called because I use the direct sources. Plus Gentoo makes keeping your system up-to-date a breeze, which is crucial is you have a system connected to the internet, and the Gentoo wiki's and help (though some can be condescending at times) is the best of any distro I've used to date.

aspasia · n00b Joined: 22 Apr 2008 Posts: 24

Thank you for your response!

I believe I did NOT select module loading - which is selecting with a * and not M - so that the drivers are built into the kernel ....

I will try again in the background as I proceed with my other tasks; yes, I use grub, to be consistent with the other distros and flavors in our lab - ...

thanks for your support and response ... I did think so that Gentoo indeed does not have a standard installation process ...Come to think of it, is there a way of doing "genkernel" instead and automatically detecting what the current drivers are and compiling it automatically?

thanks again.

aspasia.

dageyra · Posted: Wed Apr 23, 2008 6:37 pm Post subject:

Genkernel is the automated way of installing the kernel, but I don't use it so I can't really help you out in that area. Your grub suggests that you have /dev/sda2 on /, is this correct? If so, did you create a swap and boot partition? Typicaly /boot ins /dev/sda1, swap is /dev/sda2, and / usually becomes /dev/sda3. From the fact that it's recognizing /dev/sda2 as ext3, I can tell it's not a swap partition, so I'm assuming /dev/sda1 is your swap and you don't have a dedicated boot partition.

You are correct, M next to a driver means it's loaded as a module and * means it's compiled directly into the kernel.

aspasia · n00b Joined: 22 Apr 2008 Posts: 24

hi thanks for your observations ...

I don't have a swap partition - intentionally - I simply want to install Gentoo and then install open-iscsi - and then create an iSCSI root - no swap - this is only for test purposes ....

hence my devices are:

/dev/sda1 --> /boot partition
/dev/sda2 --> / partition

I may try genkernel and see ...

dageyra · Posted: Wed Apr 23, 2008 8:59 pm Post subject:

Another way to get help is on freenode.net, #gentoo, there is almost always someone around who can help in the IRC channels. They can take a closer look at your grub to see what is going on.

aspasia · n00b Joined: 22 Apr 2008 Posts: 24

thanks! I will try that too .. though they can be condescending at times .. ;-)

thanks again for your support!

C1REX · l33t Joined: 02 Jan 2004 Posts: 774 Location: Poland/UK

New gentoo sources didn't work for me. I had exactly the same problem and couldn't fix it. Very bad start with gentoo after 2 years break.
I used older version kernel-2.6.22-gentoo-r10 and it worked,

Looks like there is a bug in version *24 and *25.
_________________
CLICK HERE to help move gentoo up on distrowatch.

If you like Gentoo you can thank devs here - https://www.gentoo.org/donate/

aspasia · n00b Joined: 22 Apr 2008 Posts: 24

Thanks for the input .. I'll try the suggested kernel version you mention to check then ... btw - not sure how gentoo tracks bugs ... is there a reference number or bug number somewhere that tracks as well as describes this issue?

thanks again ... cheers,

aspasia.

NeddySeagoon · Posted: Fri Apr 25, 2008 3:31 pm Post subject:

aspasia,

You do not have the drivers for your disk controller in the kernel.

There is a bug in 2.6.24 is that it does not pick up the default configuration which leaves a lot of essential options turned off.
e.g. PCI bus support, which in turn hides all drivers that make use of the PCI bus, which is most things.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

aspasia · n00b Joined: 22 Apr 2008 Posts: 24

Thanks much for the clarification!

cheers,

aspasia.

AndrejaKo · n00b Joined: 25 Apr 2008 Posts: 25

I have same problem as aspasia. My /dev/sda1 is boot, /dev/sda2 is swap , /dev/sda3 is root and /dev/sda4 is for other systems. Also running 2.6.24-gentoo-r4. I have nforce2 motherboard with Sil3112 sata controller and I remember that while looking among drivers I found driver for Sil3112 and compiled it in kernel. I did the same for pata driver, and hdd connected to is shown as recommended option for root. I read through all options in menuconfig and enabled PCI support among other things

aspasia · n00b Joined: 22 Apr 2008 Posts: 24

Hi Andrejako,

so were you able to successfully boot a new Gentoo install afer finding the exact drivers?

thx

-a

NeddySeagoon · Posted: Fri Apr 25, 2008 10:03 pm Post subject:

AndrejaKo,

Welcome to Gentoo.

I have an nforce2 based board with the SIL 3112 too.
In Device Drivers ----> set

DeIM · Guru Joined: 11 Apr 2006 Posts: 429

I've deleted root=/dev/sda3 after kernel part and it boots ok I've grub 0.9.7-r4

DeIM · Guru Joined: 11 Apr 2006 Posts: 429

after sucessfull boot i returned root=/dev/sda3 back and it works fine

AndrejaKo · n00b Joined: 25 Apr 2008 Posts: 25

I have managed to boot into Gentoo with NeddySeagoon´s instructions.

aspasia · n00b Joined: 22 Apr 2008 Posts: 24

thank you so much tooo!!!! after following the above instructions all necessary HW drivers booted correctly!!!!

I have a new problem but it is out of topic, I'll open a new one.

Thanks so much again - guess this issue is solved!

- aspasia.