ZFS A problem with booting FreeBSD on ZFS

S

Snake89

Good day!

Problem: after rebooting the server version 11.1, an error flies to the screen (see screenshots)
unable to remount devfs under /dev

6118


Tell me, is there a solution to restore server load?
 
I'm a little puzzled by the unable to unlink /dev/dev. And I'm wondering how it loads the kernel if it can't find the filesystem (the kernel is stored on the filesystem).

What filesystem is the server using? UFS? Anything advanced like full disk encryption? Have you tried booting a rescue image? Are the disk(s) still good?
 
SirDice said:
I'm a little puzzled by the unable to unlink /dev/dev. And I'm wondering how it loads the kernel if it can't find the filesystem (the kernel is stored on the filesystem).

What filesystem is the server using? UFS? Anything advanced like full disk encryption? Have you tried booting a rescue image? Are the disk(s) still good?
Click to expand...

using - ZFS

Tried to be started on the copy of the boot catalog from an image, the decision came true
 
I ran into this same issue on a custom install of FreeBSD. The more informative error turned out to be mountroot: unable to remount devfs under /dev, which led me to believe that my root filesystem wasn't being mounted correctly. In fact, it wasn't and it was due to an incorrect entry in /boot/loader.conf:

The entry vfs.root.mountfrom="zfs:zroot" should have been vfs.root.mountfrom="zfs:zroot/ROOT/default", which conforms to FreeBSD's default ZFS Boot Environment layout on used for ZFS Root installs.
 
mountroot: unable to remount devfs under /dev
I spent many hours on same error today.
Fix for me was to create empty /dev /tmp /proc
 
Daniil said:
mountroot: unable to remount devfs under /dev
I spent many hours on same error today.
Fix for me was to create empty /dev /tmp /proc
Click to expand...
Thank you for this really helpful message.

To elaborate your short note a bit in more detail. This error means that the root (initrd) filesystem tries to set its mount point under /dev. But where /dev is coming from, if there is no filesystem before the root itself? The answer is: /dev is provided by the root filesystem. So it mounts to itself, sort of. That's why the root filesystem must contain /dev.

The error means /dev is not there, for some reason. If root filesystem is created manually as in my experiment. Or if the installer has failed to write the actual content to a partition in case of other reporters, I suppose.
 
This looks like a screenshot from VirtualBox... Normally, if you try to create a VirtualBox machine, you tell it at the start to set things up for FreeBSD 64-bit, and then the rest will get taken care of for you. Dunno if that was the case in 2019, though.
 
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