linux/Documentation/filesystems/nfs-rdma.txt

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#				NFS/RDMA README				       #
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 Author: NetApp and Open Grid Computing
 Date: May 29, 2008

Table of Contents
~~~~~~~~~~~~~~~~~
 - Overview
 - 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.

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

  If you get stuck, you can ask questions on the

                nfs-rdma-devel@lists.sourceforge.net

  mailing list.

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, the
    Ammasso AMS1100 iWARP adapter, and the Chelsio cxgb3 iWARP adapter.

  - Install a Linux distribution and tools

    The first kernel release to contain both the NFS/RDMA client and server was
    Linux 2.6.25  Therefore, a distribution compatible with this and subsequent
    Linux kernel release should be installed.

    The procedures described in this document have been tested with
    distributions from Red Hat's Fedora Project (http://fedora.redhat.com/).

  - Install nfs-utils-1.1.2 or greater on the client

    An NFS/RDMA mount point can be obtained by using the mount.nfs command in
    nfs-utils-1.1.2 or greater (nfs-utils-1.1.1 was the first nfs-utils
    version with support for NFS/RDMA mounts, but for various reasons we
    recommend using nfs-utils-1.1.2 or greater). To see which version of
    mount.nfs you are using, type:

    $ /sbin/mount.nfs -V

    If the version is less than 1.1.2 or the command does not exist,
    you should install the latest version of nfs-utils.

    Download the latest package from:

    http://www.kernel.org/pub/linux/utils/nfs

    Uncompress the package and follow the installation instructions.

    If you will not need the idmapper and gssd executables (you do not need
    these to create an NFS/RDMA enabled mount command), the installation
    process can be simplified by disabling these features when running
    configure:

    $ ./configure --disable-gss --disable-nfsv4

    To build nfs-utils you will need the tcp_wrappers package installed. For
    more information on this see the package's README and INSTALL files.

    After building the nfs-utils package, there will be a mount.nfs binary in
    the utils/mount directory. This binary can be used to initiate NFS v2, v3,
    or v4 mounts. To initiate a v4 mount, the binary must be called
    mount.nfs4.  The standard technique is to create a symlink called
    mount.nfs4 to mount.nfs.

    This mount.nfs binary should be installed at /sbin/mount.nfs as follows:

    $ sudo cp utils/mount/mount.nfs /sbin/mount.nfs

    In this location, mount.nfs will be invoked automatically for NFS mounts
    by the system mount commmand.

    NOTE: mount.nfs and therefore nfs-utils-1.1.2 or greater is only needed
    on the NFS client machine. You do not need this specific version of
    nfs-utils on the server. Furthermore, only the mount.nfs command from
    nfs-utils-1.1.2 is needed on the client.

  - Install a Linux kernel with NFS/RDMA

    The NFS/RDMA client and server are both included in the mainline Linux
    kernel version 2.6.25 and later. This and other versions of the 2.6 Linux
    kernel can be found at:

    ftp://ftp.kernel.org/pub/linux/kernel/v2.6/

    Download the sources and place them in an appropriate location.

  - Configure the RDMA stack

    Make sure your kernel configuration has RDMA support enabled. Under
    Device Drivers -> InfiniBand support, update the kernel configuration
    to enable InfiniBand support [NOTE: the option name is misleading. Enabling
    InfiniBand support is required for all RDMA devices (IB, iWARP, etc.)].

    Enable the appropriate IB HCA support (mlx4, mthca, ehca, ipath, etc.) or
    iWARP adapter support (amso, cxgb3, etc.).

    If you are using InfiniBand, be sure to enable IP-over-InfiniBand support.

  - Configure the NFS client and server

    Your kernel configuration must also have NFS file system support and/or
    NFS server support enabled. These and other NFS related configuration
    options can be found under File Systems -> Network File Systems.

  - Build, install, reboot

    The NFS/RDMA code will be enabled automatically if NFS and RDMA
    are turned on. The NFS/RDMA client and server are configured via the hidden
    SUNRPC_XPRT_RDMA config option that depends on SUNRPC and INFINIBAND. The
    value of SUNRPC_XPRT_RDMA will be:

     - N if either SUNRPC or INFINIBAND are N, in this case the NFS/RDMA client
       and server will not be built
     - M if both SUNRPC and INFINIBAND are on (M or Y) and at least one is M,
       in this case the NFS/RDMA client and server will be built as modules
     - Y if both SUNRPC and INFINIBAND are Y, in this case the NFS/RDMA client
       and server will be built into the kernel

    Therefore, if you have followed the steps above and turned no NFS and RDMA,
    the NFS/RDMA client and server will be built.

    Build a new kernel, install it, boot it.

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 cleint'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

    If the NFS/RDMA server was built as a module (CONFIG_SUNRPC_XPRT_RDMA=m in
    kernel config), load the RDMA transport module:

    $ modprobe svcrdma

    Regardless of how the server was built (module or built-in), start the
    server:

    $ /etc/init.d/nfs start

    or

    $ service nfs start

    Instruct the server to listen on the RDMA transport:

    $ echo rdma 2050 > /proc/fs/nfsd/portlist

  - On the client system

    If the NFS/RDMA client was built as a module (CONFIG_SUNRPC_XPRT_RDMA=m in
    kernel config), load the RDMA client module:

    $ modprobe xprtrdma.ko

    Regardless of how the client was built (module or built-in), use this
    command to mount the NFS/RDMA server:

    $ mount -o rdma,port=2050 <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!