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 Author: NetApp and Open Grid Computing
 
 Adapted for OFED 1.4 (from linux-2.6.27.8/Documentation/filesystems/nfs-rdma.txt)
 by Jeff Becker

Table of Contents
~~~~~~~~~~~~~~~~~
 - Overview
 - OFED 1.4 limitations
 - Getting Help
 - Installation
 - Check RDMA and NFS Setup
 - NFS/RDMA Setup

Overview
~~~~~~~~

  This document describes how to install and setup the Linux NFS/RDMA client
  and server software.

  The NFS/RDMA client was first included in Linux 2.6.24. The NFS/RDMA server
  was first included in the following release, Linux 2.6.25.

  In our testing, we have obtained excellent performance results (full 10Gbit
  wire bandwidth at minimal client CPU) under many workloads. The code passes
  the full Connectathon test suite and operates over both Infiniband and iWARP
  RDMA adapters.

OFED 1.4.1 limitations:
~~~~~~~~~~~~~~~~~~~~~
  NFS-RDMA is supported for the following releases:
  - Redhat Enterprise Linux (RHEL) version 5.1
  - Redhat Enterprise Linux (RHEL) version 5.2
  - Redhat Enterprise Linux (RHEL) version 5.3
  - SUSE Linux Enterprise Server (SLES) version 10, Service Pack 2
  - SUSE Linux Enterprise Server (SLES) version 11

  And the following kernel.org kernels:
  - 2.6.22
  - 2.6.26
  - 2.6.27

  All other Linux Distrubutions and kernel versions are NOT supported on OFED 1.4.1

Getting Help
~~~~~~~~~~~~

  If you get stuck, you can ask questions on the
  nfs-rdma-devel@lists.sourceforge.net, or general@lists.openfabrics.org
  mailing lists.

Installation
~~~~~~~~~~~~

  These instructions are a step by step guide to building a machine for
  use with NFS/RDMA.

  - Install an RDMA device

    Any device supported by the drivers in drivers/infiniband/hw is acceptable.

    Testing has been performed using several Mellanox-based IB cards and 
    the Chelsio cxgb3 iWARP adapter.

  - Install OFED 1.4.1

    NFS/RDMA has been tested on RHEL5.1, RHEL5.2, RHEL 5.3, SLES10SP2, SLES11,
    kernels 2.6.22, 2.6.26, and 2.6.27.  On these kernels, NFS-RDMA will be
    installed by default if you simply select "install all", and can be
    specifically included by a "custom" install.

    In addition, the install script will install a version of the nfs-utils that
    is required for NFS/RDMA.  The binary installed will be named "mount.rnfs".
    This version is not necessary for Linux Distributions with nfs-utils 1.1 or
    later.

    Upon successful installation, the nfs kernel modules will be placed in the
    directory /lib/modules/'uname -a'/updates. It is recommended that you reboot to
    ensure that the correct modules are loaded.

Check RDMA and NFS Setup
~~~~~~~~~~~~~~~~~~~~~~~~

    Before configuring the NFS/RDMA software, it is a good idea to test
    your new kernel to ensure that the kernel is working correctly.
    In particular, it is a good idea to verify that the RDMA stack
    is functioning as expected and standard NFS over TCP/IP and/or UDP/IP
    is working properly.

  - Check RDMA Setup

    If you built the RDMA components as modules, load them at
    this time. For example, if you are using a Mellanox Tavor/Sinai/Arbel
    card:

    $ modprobe ib_mthca
    $ modprobe ib_ipoib

    If you are using InfiniBand, make sure there is a Subnet Manager (SM)
    running on the network. If your IB switch has an embedded SM, you can
    use it. Otherwise, you will need to run an SM, such as OpenSM, on one
    of your end nodes.

    If an SM is running on your network, you should see the following:

    $ cat /sys/class/infiniband/driverX/ports/1/state
    4: ACTIVE

    where driverX is mthca0, ipath5, ehca3, etc.

    To further test the InfiniBand software stack, use IPoIB (this
    assumes you have two IB hosts named host1 and host2):

    host1$ ifconfig ib0 a.b.c.x
    host2$ ifconfig ib0 a.b.c.y
    host1$ ping a.b.c.y
    host2$ ping a.b.c.x

    For other device types, follow the appropriate procedures.

  - Check NFS Setup

    For the NFS components enabled above (client and/or server),
    test their functionality over standard Ethernet using TCP/IP or UDP/IP.

NFS/RDMA Setup
~~~~~~~~~~~~~~

  We recommend that you use two machines, one to act as the client and
  one to act as the server.

  One time configuration:

  - On the server system, configure the /etc/exports file and
    start the NFS/RDMA server.

    Exports entries with the following formats have been tested:

    /vol0   192.168.0.47(fsid=0,rw,async,insecure,no_root_squash)
    /vol0   192.168.0.0/255.255.255.0(fsid=0,rw,async,insecure,no_root_squash)

    The IP address(es) is(are) the client's IPoIB address for an InfiniBand
    HCA or the client's iWARP address(es) for an RNIC.

    NOTE: The "insecure" option must be used because the NFS/RDMA client does
    not use a reserved port.

 Each time a machine boots:

  - Load and configure the RDMA drivers

    For InfiniBand using a Mellanox adapter:

    $ modprobe ib_mthca
    $ modprobe ib_ipoib
    $ ifconfig ib0 a.b.c.d

    NOTE: use unique addresses for the client and server

  - Start the NFS server

    Load the RDMA transport module:

    $ modprobe svcrdma

    Start the server:

    $ /etc/init.d/nfsserver start

    or

    $ service nfs start

    Instruct the server to listen on the RDMA transport:

    $ echo rdma 20049 > /proc/fs/nfsd/portlist

  - On the client system

    Load the RDMA client module:

    $ modprobe xprtrdma

    Mount the NFS/RDMA server:

    $ mount -o rdma,port=20049 <IPoIB-server-name-or-address>:/<export> /mnt

    To verify that the mount is using RDMA, run "cat /proc/mounts" and check
    the "proto" field for the given mount.

  Congratulations! You're using NFS/RDMA!

Known Issues
~~~~~~~~~~~~~~~~~~~~~~~~

If you're running NFSRDMA over Chelsio's T3 RNIC and your cients are using
a 64KB page size (like PPC64 and IA64 systems) and your server is using a
4KB page size (like i386 and X86_64), then you need to mount the server
using rsize=32768,wsize=32768 to avoid overrunning the Chelsio RNIC fast
register limits.  This is a known firmware limitation in the Chelsio RNIC.
