14.3.31. Using NFSv3 for NFS Root Filesystem

Question:

My NFS server only allows the protocol in version 3. Even though my kernel has "NFS client support for NFS version 3" compiled in, I cannot use this as a root filesystem. The boot process stops like this:

Looking up port of RPC 100003/2 on 10.0.0.136
Looking up port of RPC 100005/1 on 10.0.0.136
Root-NFS: Server returned error -22 while mounting /opt/eldk/ppc_6xx
VFS: Unable to mount root fs via NFS, trying floppy.
VFS: Cannot open root device "nfs" or unknown-block(2,0)

Answer:

In addition to the kernel support, you need to specify the "nfsvers=3" option to use NFS protocol version 3 as a rootfilesystem. So include something like the following in your kernel commandline:

nfsroot=[<server-ip>:]<root-dir>,nfsvers=3