Chapter 6. Enabling NFS over RDMA on an NFS server
Remote Direct Memory Access (RDMA) is a protocol that enables a client system to directly transfer data from the memory of a storage server into its own memory. This enhances storage throughput, decreases latency in data transfer between the server and client, and reduces CPU load on both ends. If both the NFS server and clients are connected over RDMA, clients can use NFSoRDMA to mount an exported directory.
Prerequisites
- The NFS service is running and configured
- An InfiniBand or RDMA over Converged Ethernet (RoCE) device is installed on the server.
- IP over InfiniBand (IPoIB) is configured on the server, and the InfiniBand device has an IP address assigned.
Procedure
Install the
rdma-corepackage:# dnf install rdma-coreIf the package was already installed, verify that the
xprtrdmaandsvcrdmamodules in the/etc/rdma/modules/rdma.conffile are uncommented:# NFS over RDMA client support xprtrdma # NFS over RDMA server support svcrdma
Optional. By default, NFS over RDMA uses port 20049. If you want to use a different port, set the
rdma-portsetting in the[nfsd]section of the/etc/nfs.conffile:rdma-port=<port>Open the NFSoRDMA port in
firewalld:# firewall-cmd --permanent --add-port={20049/tcp,20049/udp} # firewall-cmd --reload
Adjust the port numbers if you set a different port than 20049.
Restart the
nfs-serverservice:# systemctl restart nfs-server
Verification
On a client with InfiniBand hardware, perform the following steps:
Install the following packages:
# dnf install nfs-utils rdma-coreMount an exported NFS share over RDMA:
# mount -o rdma server.example.com:/nfs/projects/ /mnt/If you set a port number other than the default (20049), pass
port=<port_number>to the command:# mount -o rdma,port=<port_number> server.example.com:/nfs/projects/ /mnt/Verify that the share was mounted with the
rdmaoption:# mount | grep "/mnt" server.example.com:/nfs/projects/ on /mnt type nfs (...,proto=rdma,...)
Additional resources
