White Papers

Introduction
5 PVRDMA Deployment and Configuration of QLogic CNA devices in VMware ESXi | Technical White
Paper | 401
1 Introduction
This document is intended to help the user understand Remote Direct Memory Access and provides step-by-
step instructions to configure the RDMA or RoCE feature on Dell EMC PowerEdge server with QLogic
network card on VMware ESXi.
1.1 Audience and Scope
This white paper is intended for IT administrators and channel partners planning to configure Paravirtual
RDMA on Dell EMC PowerEdge servers. PVRDMA is a feature that is aimed at customers who are
concerned with faster data transfer between hosts that are configured with PVRDMA, and to ensure less CPU
utilization with reduced cost.
1.2 Remote Direct Memory Access
Note: The experiments described here are conducted using the Dell EMC PowerEdge R7525 server.
RDMA allows us to perform direct data transfer in and out of a server by implementing a transport protocol in
the network interface card (NIC) hardware. The technology supports zero-copy networking, a feature that
enables data to be read directly from the main memory of one system and then write the data directly to the
main memory of another system.
If the sending device and the receiving device both support RDMA, then the communication between the two
is quicker when compared to non-RDMA network systems.
RDMA workflow
The RDMA workflow figure shows a standard network connection on the left and an RDMA connection on the
right. The initiator and the target must use the same type of RDMA technology such as RDMA over
Converged Ethernet or InfiniBand.
Studies have shown that RDMA is useful in applications that require fast and massive parallel high-
performance computing (HPC) clusters and data center networks. It is also useful when analyzing big data, in
supercomputing environments that process applications, and for machine learning that requires lower
latencies with higher data transfer rates. RDMA is implemented in connections between nodes in compute
clusters and in latency-sensitive database workloads. For more information about the studies and discussions
carried out on RDMA, see www.vmworld.com.