On Sat, Jun 25, 2016 at 2:33 PM, Helmut Jarausch <jarau...@skynet.be> wrote: > > I'm a dino since I still use grub-1 but I prefer recent kernels (currently > 4.70-rc4) > > I don't understand the 'root=' option on the boot line like > kernel /boot/vmlinuz-4.7.0-rc4 root=/dev/sda1 > > Here my bad experience: > > Having booted by SystemRescueCD from the cdrom device, my root device is > labelled /dev/sda1 > BUT trying to use that on the kernel boot line fails (the kernel cannot > find the root file system) > > By trial and error I've found that I have to use root=/dev/sdb1 > > but if I plug in an external drive (via USB) this doesn't work any more. > > So, I came up with root=UUID=uuid_number of the root file system. > > But to my surprise I now got a kernel panic > syncing: VFS: unable to mount root fs on unknown block(0,0) > > So, please tell me what I'm missing?
Are you using an initramfs? You can't use "root=UUID=uuid" if you don't. You can use "root=PARTUUID=partuuid" where on an msdos-labeled disk: # findmnt / -o TARGET,SOURCE,PARTUUID TARGET SOURCE PARTUUID / /dev/sda1 0006c8d7-01 on a gpt-labeled disk: # findmnt / -o TARGET,SOURCE,PARTUUID TARGET SOURCE PARTUUID / /dev/sda3 41e9268f-484a-43e2-ae81-54d8c84119e0
