Re: FreeBSD nfsroot - will it work with NFSv4.2?

On Thu, Feb 19, 2026 at 2:23 PM Dan Shelton <[email protected]> wrote:
>
> Hello,
>
> Will a FreeBSD 15.0 diskless setup with nfsroot work with NFSv4.2?
I just committed a patch to main that does this, with some limitations.
It will be in 15.1.

The limitations are:
- The server must be configured to handle both NFSv3 and NFSv4
  because the bootstrap code still uses NFSv3.
- The root directory specified in the "V4:" line in /etc/exports must
  be "/" so that the root-path is the same for an NFSv3 and NFSv4 mount.
- The NFSv4 server must be configured to use id-numbers in strings and
  not be running the nfsused(8) daemon. (This limitation might be lifted
  in a future commit which hard-wires enough mapping info to make
  things work until the nfsuserd(8) daemon is running.)

The NFSv4 mount is enabled by putting:
boot.nfsroot.options="nfsv4"
in the root fs's /boot/loader.conf in the NFS server.
It also needs:
vfs.nfs.enable_uidtostring=1
in /etc/sysctl.conf in the root fs in the NFS server.

I found Mateusz's wiki useful for the rest of the setup:
https://wiki.freebsd.org/MateuszPiotrowski/BootFreebsdFromNfs

I also did a couple of things...
- Deleted /etc/hostid in the root fs in the NFS server, so that each
  client gets a unique kern.hostuuid.
- Added a line like:
  tmpfs /tmp tmpfs rw,size=10M,mode=01777 0 0
  to the /etc/fstab in the root fs in the NFS server, so /tmp was
  mounted.

Good luck with it, rick
>
> Dan
> --
> Dan Shelton - Cluster Specialist Win/Lin/Bsd
>