Op Fri, 02 Oct 2009 01:38:29 +0200 schreef Baho Utot <baho-u...@columbus.rr.com>:
> Hans Kaper wrote: >> Op Thu, 01 Oct 2009 00:19:29 +0200 schreef Baho Utot >> <baho-u...@columbus.rr.com>: >> >> >>> J.P.Kaper wrote: >>> >>>> I am building LFS from book 6.4 on an ext3 logical partition of an >>>> external USB harddisk. >>>> My host system is SUSE 10.3 on one of my two internal harddisks. >>>> >>>> Booting from the USB disk fails with >>>> "[4.410067] Kernel panic - not syncing: VFS: Unable to mount >>>> root fs on unknown-block (2,0)" >>>> >>>> >>>> >>> I have done some more research on your problem. >>> >>> Try this >>> >>> in /etc/fstab for the USB disk >>> >>> UUID=6342a6b5-25cf-4d01-a318-68309d12ab5b / ext3 defaults 1 1 >>> >>> change the blkid to the correct value based on >>> $ blkid /dev/sdxx >>> >>> >>> Are you trying to boot with grub on the USB drive? >>> If so try changing /boot/grub/menu.lst kernel line like this >>> >>> kernel /boot/lfskernel-2.6.30.2 root=/dev/sdd1 rootdelay=15 ro quite >>> >>> change the /dev/sdd1 to the correct value for your USB drive >>> >>> >>> If you have success then try to use UUID in the menu.lst file like this >>> >>> kernel /boot/lfskernel-2.6.30.2 >>> root=UUID=6342a6b5-25cf-4d01-a318-68309d12ab5b rootdelay=15 ro quite >>> >>> >> > > It looks like grub or the kernel can give the kernel panic about not > syncing. > > I like to use UUID or LABEL in grubs menu.lst file. > > Grub can process UUID of LABELs and it makes sure that the > drive/partition > that you are trying to boot doesn't change or get mixed up. ( It keeps > me from getting mixed up > trying to keep "whos bootin from here to where ?" straight ) > > But..... > > After you can successfully load/execute the kernel, and grubs done it's > work.... > I think the kernel can not locate its root file system and barfs giving > the kernel panic. > > I have found that UUID or LABELs in /etc/fstab gives you the kernel > panic because the kernel can not process UUID or LABELs > without using a initrd as udev has not been started. So you need to use > /dev/sdx there. > > example: > > title LFS 6.5 - USB > root (hd0,0) > kernel /boot/lfskernel-2.6.30.2 root=/dev/sdd1 rootdelay=15 ro quite > > That makes the USB tied to that PC :( > > If you need it to boot on another PC you need to edit the grub line from > the menu when grubs starts up or use an initrd. > > Hope this helps. > You are right. root=/dev/sdc8 works fine. root=UUID=......... fails with a Grub-error 11: Unrecognized device string. My intention was indeed to use LFS on the usb-disk on different computers. Maybe I will try to build an initrd sometime, just as an exercise; changing the Grub-line every time I change computers looks not very neat to me. But as you have seen in the post from Danny Engelbarts, leaving out the root= altogether is an even simpler solution. I think we can close this thread now. I am very grateful for your interest; your suggestions have brought me a good step further in understanding the workings of Linux. Hans Kaper. -- -- http://linuxfromscratch.org/mailman/listinfo/lfs-support FAQ: http://www.linuxfromscratch.org/lfs/faq.html Unsubscribe: See the above information page
