The user-space NFS server traditionally used in Linux works reliably but
suffers performance problems when overworked. This is primarily because
of the overhead the system call interface adds to its operation, and because
it must compete for time with other, potentially less important, user-space
processes.
The 2.2.0 kernel supports an experimental kernel-based NFS server developed
by Olaf Kirch and further developed by H.J. Lu, G. Allan Morris, and Trond
Myklebust. The kernel-based NFS support provides a significant boost in server
performance.
In current release distributions, you may find the server tools
available in prepackaged form. If not, you can locate them at
https://csua.berkeley.edu/~gam3/knfsd/. You need to
build a 2.2.0 kernel with the kernel-based NFS daemon
included in order to make use of the tools. You can check if your
kernel has the NFS daemon included by looking to see if the
/proc/sys/sunrpc/nfsd_debug file exists. If it's
not there, you may have to load the rpc.nfsd module
using the modprobe utility.
The kernel-based NFS daemon uses a standard
/etc/exports configuration file. The package
supplies replacement versions of the rpc.mountd and
rpc.nfsd daemons that you start much the same way
as their userspace daemon counterparts.
