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Commit a3fa73bd authored by James Lentini's avatar James Lentini Committed by J. Bruce Fields
Browse files

Documentation: NFS/RDMA instructions for 2.6.25-rc1 



Add some instructions for using the new NFS/RDMA features.

Signed-off-by: default avatarJames Lentini <jlentini@netapp.com>
Cc: Roland Dreier <rdreier@cisco.com>
Signed-off-by: default avatarJ. Bruce Fields <bfields@citi.umich.edu>
parent a277e33c

Documentation/filesystems/nfs-rdma.txt

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################################################################################

#									       #

#				NFS/RDMA README				       #

#									       #

################################################################################



 Author: NetApp and Open Grid Computing

 Date: February 25, 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-1.1.1 or greater on the client



    An NFS/RDMA mount point can only be obtained by using the mount.nfs

    command in nfs-utils-1.1.1 or greater. To see which version of mount.nfs

    you are using, type:



    > /sbin/mount.nfs -V



    If the version is less than 1.1.1 or the command does not exist,

    then you will need to 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 be using GSS and NFSv4, the installation process

    can be simplified by disabling these features when running configure:



    > ./configure --disable-gss --disable-nfsv4



    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.



    NOTE: mount.nfs and therefore nfs-utils-1.1.1 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-1.1.1 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 format have been tested:



    /vol0   10.97.103.47(rw,async) 192.168.0.47(rw,async,insecure,no_root_squash)



    Here the first IP address is the client's Ethernet address and the second

    IP address is the clients IPoIB address.



 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), issue the mount.nfs command:



    > /path/to/your/mount.nfs <IPoIB-server-name-or-address>:/<export> /mnt -i -o rdma,port=2050



    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!