On 19/03/16 20:28, Ken Moffat wrote:
On Sat, Mar 19, 2016 at 04:09:39PM -0400, N. Morris wrote:
After rebooting multiple times and checking files and filesystems I do not
know how to solve the current problem I am facing:
In the fstab file I have the root fs and swap locations at their UUID and
all the other stuff as it looks on the website.
That is your problem, as I see you have guessed - the kernel only
understands devices.
For grub.cfg try /dev/sdd2 for the kernel and then similar variants
for swap and anything else mounted from /etc/fstab. But read on -
the drive might appear at a different device, and it might appear
late.
NB for fstab the entry for '/' is effectively a comment.
I have it as the UUID since its a usb external hdd and I'm booting on
different computers all the time.
The partition where lfs is is /dev/sdd2
At the grub prompt I do :
set root=(hd2,msdos2)
ls (hd2,msdos2)
<info...info..info..UUID <uuid>>
linux /boot/vmlinuz-4.5.0 root=UUID=<uuid goes here>
boot
I did it like that because that is how the grub config on my drive with
ubuntu on it looks.
I also tried where root=/dev/sdc1 and somehow successfully booted my
partition with fedora on it. But that would be linux mostly not from
scratch.
The kernel always panics and says : cannot open root device UUID=<uuid> or
unknown block (0,0) error -6
Do I have to use the root=/dev/sdXX method in grub and in fstab or do I
have to enable some obscure option during kernel config or is it because
I'm using an external HDD or something else?
Thanks for your help.
Adding an external drive might make it harder - when there is more
than one drive (and you have at least four) different kernels can
report them in different orders : on one of my machines, adding a
second drive with some other OS, as the second drive according to
grub, made linux think it was the first drive, and adding a third
drive to copy everything onto meant the original drive was now sdc.
These situations are why distros use UUID - but for that to work you
need to use an initrd. An example is covered in BLFS:
http://www.linuxfromscratch.org/blfs/view/svn/postlfs/initramfs.html
For external drives, people have reported having to add a kernel
parameter to cause it to wait for the rootfs to appear - I am not
sure if that is needed or not with an initrd (I've never used
either).
ĸen
I have put lfs on usb drives at 1st i was able to add the rootwait to
the kernal line but latley it hasn't work and ended up using the initrd
which solved the problem, as Ken mentioned it,s in the blfs book
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