VFS: cannot open root device "sda3" or unknown-block (0,0)
 

i just finished installing gentoo and after rebooting and able to boot, the booting process goes on for like 5 seconds and then it stops complaining that "sda3" is not real root.

here is the exact message

VFS: cannot open root device "sda3" or unknown-block (0,0)
please append a correct "root=" boot option
kernel panic- not syncing: VFS: unable to mount root fs on unknow-block(0,0)

here is my /etc/fstab

/dev/sda1 /boot ext2 noauto,noatime 1 2
/dev/sda3 / xfs noatime 0 1
/dev/sda2 none swap sw 0 0
/dev/sda4 /home xfs noatime 0 1
/dev/cdroms/cdrom /mnt/cdrom auto noauto,user 0 0
#/dev/fd0 /mnt/floppy auto noauto,user 0 0

none /proc proc defaults 0 0

none /dev/shm tmpfs nodev,nosuid,noexec 0 0

here is my grub.conf file

default 0
timeout 30
splashimage=(hd0,0)/boot/grub/splash.xpm.gz

title= Gentoo Linux 2.6.15

root (hd0,0)
kernel /kernel-2.6.15-gentoo-r1 root=/dev/sda3


thanks in advance

Looks like your kernel lacks some hardware support. SATA or SCSI controller is not recognized, I guess.

if you used genkernel you may be forgetting the 'initrd' part of teh grub configuration.

i compiled the kernel manually and i have recompiled twice to ensure that i inclueded support for sata and scsi device and still no go. does it make a different if i go back and recompiled using genkernel ? my first try, i used genkernel but it just hanged and nothing happened so i rebooted and compiled manually. any advise will be apreciated

You need support for your chipset naturally. lspci -v and lshw can give you clue what exactly do you have there.

i recompiled using genkernel, rebooted and now im getting a different error message

>>loading Modules
>>activating udev
>>determining /dev/sda3 is not a valid root device
!! Block device /dev/sda3 is not a valid root device...
!!The root bolck device is unspecified or not detected

please specify a device to boot, or "shell" for shell

boot() ::

anyone? anyone?

Hm. Make sure you have your SATA contoller support and root filesystem (XFS) support compiled in (not as module) - then it works. Unless you want to fiddle with initrd, never used it myself.

hey thanks for the reply emerson. i have compiled the kernel both manually and via genkernel at least 6 times and i have ensure that support for scsi devices and all filesystems are built in to the kernel and still getting the same message. I was able to successfully installed gentoo before but i was using linux-2.6.14-gentoo-r1 so maybe the new kernel does not like sata drives. maybe i'll download that kernel and try to install it again, see if that works. other than that, i cant think of anything else. the one thing that i did which i dont know if it makes a difference or not is that after assigning filesystmes to my / & /home partition, i edited the fstab file and changed them to ext3 and later on changed them back to xfs. i really doubht that this change is causing the problem.

Maybe it is. Unless you allready build in support for your xfs to the kernel.

http://www.gentoo.org/doc/en/handboo...?part=1&chap=7

Your grub.conf should looke like this:
Replacing the version with your current offcourse.

I've had this error several times before and I solved it by using genkernel, and afterwards added the above info to my grub.conf.
http://www.gentoo.org/doc/en/handboo...part=1&chap=10

Similar problem can be found here:
http://forums.gentoo.org/viewtopic-t...block+0+0.html

Hope this gets you going :)


Sincerely, Jørgen

I need support for SCSI. I didn't know that the kernel saw modern harddrives as SCSI. I thought it was referring to old obsoleted hardware. This problem is fixed, onto the next!

EDIT: And no, I did not need an initramfs. I'm booted up just fine without it. According to the gentoo handbook, you only need that if you have separate partitions for things such as /usr and /etc/. I just have partitions for / /boot /home and swap.