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componentscience

Member

Registered: 2024-01-05

Posts: 20

[Solved] Pacstrap error: failed to detect root filesystem

When running pacstrap the following error is thrown during the mkinitcpio build: Error: failed to detect root filesystem. It appears to occur during the 'autodetect' hook.

# mkdir PacstrapTest
# pacstrap -K -c PacstrapTest base linux

# uname -a
Linux in000 6.18.2-arch2-1

Stdout & stderr
https://0x0.st/PoLC.txt

Last edited by componentscience (2026-01-05 15:47:33)

5hridhyan

Member

From: Asia

Registered: 2025-12-25

Posts: 640

Re: [Solved] Pacstrap error: failed to detect root filesystem

If this is a real install, have you mounted the target filesystem?
If it’s a directory-based build, either remove the autodetect hook or ignore the warning and if you want you can regenerate the initramfs later.

Last edited by 5hridhyan (2026-01-05 18:02:54)

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componentscience

Member

Registered: 2024-01-05

Posts: 20

Re: [Solved] Pacstrap error: failed to detect root filesystem

Yes it's a directory-based build. I will remove the hook and regenerate the initramfs in the local directory. Thank you.

Scimmia

Fellow

Registered: 2012-09-01

Posts: 13,723

Re: [Solved] Pacstrap error: failed to detect root filesystem

Wait, if this is just a directory that you're not going to boot, why are you installing a kernel and generating an initramfs at all?

cryptearth

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Registered: 2024-02-03

Posts: 2,090

Re: [Solved] Pacstrap error: failed to detect root filesystem

@Scimmia
when building kernel modules in a chroot, as an example
the current archzfs project uses clean-chroot-manager to build packages as upstream zfs only builds deb and rpm packages
for instance since some update I too get some error during the initrd build because its done whenever the chroot updates the kernel - but it doesn't affect the kmod build or packaging as this environment doesn't get bootet

componentscience

Member

Registered: 2024-01-05

Posts: 20

Re: [Solved] Pacstrap error: failed to detect root filesystem

Wait, if this is just a directory that you're not going to boot, why are you installing a kernel and generating an initramfs at all?

Correct this will not be booted from directly and doesn't require a kernel. It will be used for testing, among other purposes, for another disk image building project. I do not recall seeing this error before which is why I created the post. I may have just overlooked it in the past.

Regards

Last edited by componentscience (2026-01-05 16:57:21)

Scimmia

Fellow

Registered: 2012-09-01

Posts: 13,723

Re: [Solved] Pacstrap error: failed to detect root filesystem

@Scimmia
when building kernel modules in a chroot, as an example

That would be using mkarchroot, not pacstrap, and you would use base-devel instead of base. If that's what's going on here, things aren't going to go well.

componentscience, so why do you need a kernel for that?

Last edited by Scimmia (2026-01-05 16:34:47)

componentscience

Member

Registered: 2024-01-05

Posts: 20

Re: [Solved] Pacstrap error: failed to detect root filesystem

componentscience, so why do you need a kernel for that?

The kernel is not required. The intention was to examine very closely what pacstrap installs, and in the process stumbled into the error. I probably posted this prematurely. Thanks for the response.

cryptearth

Member

Registered: 2024-02-03

Posts: 2,090

Re: [Solved] Pacstrap error: failed to detect root filesystem

@Scimmia
when building kernel modules in a chroot, as an example

That would be using mkarchroot, not pacstrap, and you would use base-devel instead of base.

feel free to give your input: https://github.com/archzfs/archzfs
there actually are ambitions to get rid of clean-chroot-manager
maybe you can help

Scimmia

Fellow

Registered: 2012-09-01

Posts: 13,723

Re: [Solved] Pacstrap error: failed to detect root filesystem

zfs isn't something I have any interest in. clean-chroot-manager already uses mkarchroot anyway.