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