mountroot error with memory based rootfs

akash kumar akashb503 at
Fri Jun 18 05:05:03 UTC 2010


The root file system was built commenting out compact flash and enabling md0 as below in the config file for my target arch.

#device                 cf
#options        ROOTDEVNAME=\"ufs:cf0s1\"

# Use the following for RFS in mem-device
options         MD_ROOT
options         ROOTDEVNAME = \"ufs:md0\"
options         MD_ROOT_SIZE = 7264

After the kernel was built and installed using 'make buildkernel KERNCONF="configfile" and make installkernel commands.
Please let me know if you need any more info.

Bhanu Prakash.

From: Tim Judd <tajudd at>
To: akash kumar <akashb503 at>
Sent: Fri, 18 June, 2010 7:50:14 AM
Subject: Re: mountroot error with memory based rootfs

On 6/17/10, akash kumar <akashb503 at> wrote:
> Hi,
> I was trying to build root filesystem in to the kernel (i.e using /dev/md0)
> for Mips based target boards. In the process i built tool chain and kernel
> successfully.
> But when i boot the kernel on the target, it fails to mount the md0 and
> drops to mountroot prompt.
> mountroot> ufs:/dev/md0
> If you have invalid mount options, reboot, and first try the following from
> the loader prompt:
> set vfs.root.mountfrom.options=rw
> and the remove invalid mount options from /etc/fstab.
> Loader variables:
> vfs.root.mountfrom=
> vfs.root.mountform.options=
> I could see that both the above variables are unset and not sure whether
> this is by default. As i am building a cross kernel, i can't add these
> options to /boot/loader.conf files which applies to current host machine.
> Please help me where the above settings need to be added i.e which directory
> and file for the settings to effect for my target kernel build.
> Thanks,
> Akash.

Please give details on how the root filesystem image is built.

What works is to format the rootfs image without a partition or bsdlabel.

It is just unable to mount the image as specified.

More information about the freebsd-questions mailing list