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# NFS/RDMA README #
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Author: NetApp and Open Grid Computing
Date: April 15, 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 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), 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!
