Weird root and boot error

[sntimi]

Hello!

There is something wrong with my disk partitions... I can run and boot gentoo only when I have just one disk connected. I tried connecting a formated HDD but the Kernel ends panicking with this error: Unable to mount root fs on unknown-block (8,3).

Thank you for your time

[sntimi]

Hello!

There is something wrong with my disk partitions... I can run and boot gentoo only when I have just one disk connected. I tried connecting a formated HDD but the Kernel ends panicking with this error: Unable to mount root fs on unknown-block (8,3).

Thank you for your time

By the way, I tried changing the "Built-in command line" in the kernel config but it does not work

[mike155]

There's probably a parameter like 'root=/dev/sda2' in your kernel command line, right?

If you add a new disk, it could be that the kernel renames your disk containing the root partition to '/dev/sdb'. If that's the case, 'root=/dev/sda2' won't work.

A possible solution are 'Filesystem labels and UUIDs' and 'Partition labels and UUIDs', see https://wiki.gentoo.org/wiki/Handbook:A ... _and_UUIDs

[pietinger]

What @mike155 said !

But the information in the link is for /etc/fstab ... this is for later (if the kernel has already booted). You need to set it also in the kernel command line; here is a better link for describing this: https://wiki.gentoo.org/wiki/EFI_stub

The solution is: "root=PARTUUID=..."

[sntimi]

There's probably a parameter like 'root=/dev/sda2' in your kernel command line, right?

If you add a new disk, it could be that the kernel renames your disk containing the root partition to '/dev/sdb'. If that's the case, 'root=/dev/sda2' won't work.

A possible solution are 'Filesystem labels and UUIDs' and 'Partition labels and UUIDs', see https://wiki.gentoo.org/wiki/Handbook:A ... _and_UUIDs

First of all, thank you for trying to help me.

So the output of blkid is:

Code: Select all

 /dev/sdb: UUID="7C97-5221" BLOCK_SIZE="512" TYPE="vfat"
/dev/sda4: UUID="e88ca318-fee1-41e5-b97d-c693049973b4" BLOCK_SIZE="4096" TYPE="ext4" PARTLABEL="rootfs" PARTUUID="5ff2b05e-d8d6-428e-a5ff-9eea84326666"
/dev/sda2: UUID="B08C-797E" BLOCK_SIZE="512" TYPE="vfat" PARTLABEL="boot" PARTUUID="40300159-d096-43e9-ac8e-a7e1db1c053d"
/dev/sda3: UUID="4a08b526-fb84-4fa8-8934-9f361155ac6e" TYPE="swap" PARTLABEL="swap" PARTUUID="f32f239b-9143-4101-b7cd-db24fc301f78"
/dev/sda1: UUID="605a7cc3-f69c-40ce-8ccc-a34657088248" TYPE="swap" PARTLABEL="grub" PARTUUID="ebc05138-520f-4100-980f-0799c0160f7d"

I wrote in the "Built-in Kernel command line" this: root=PARTUUID=5ff2b05e-d8d6-428e-a5ff-9eea84326666.

And then I did "make && make modules_install". I tried to do "make install" but it show me this: sh ./arch/x86/boot/install.sh 5.10.27-gentoo arch/x86/boot/bzImage \ System.map "/boot".

Here is what I have in my fstab just in case you need it:

Code: Select all

/dev/sda2 /boot vfat defaults 0 2
/dev/sda3 none swap sw 0 0
/dev/sda4 / ext4 noatime 0 1

Something is wrong with this because the boot when I have two disks is still not working

[NeddySeagoon]

sntimi,

Kernel device names are allocated on a drive detection order.
Your original /dev/sda became /dev/sdb when you added a drive.

The hack is to swap motherboard connectors, so that your original sda is detected first. Thats not robust. You add more drives and you have to do it again.

The robust fix is to use root=PARTUUID= to define root in the kernel command line and either PARTUUID or the filesystem UUID in /etc/fstab.

The kernel built in command line may not be used. It is overridden by anything passed at boot time.

[sntimi]

sntimi,

Kernel device names are allocated on a drive detection order.
Your original /dev/sda became /dev/sdb when you added a drive.

The hack is to swap motherboard connectors, so that your original sda is detected first. Thats not robust. You add more drives and you have to do it again.

The robust fix is to use root=PARTUUID= to define root in the kernel command line and either PARTUUID or the filesystem UUID in /etc/fstab.

The kernel built in command line may not be used. It is overridden by anything passed at boot time.

I swapped connectors and now it is working!!!! Thank you so much Neddy