Over at Forbes, Tom Coughlin writes that RDMA extends the capability of fast direct access to memory between computers in a cluster to greater distances, within a Metropolitan Area Network (MAN ) or even in a Wide Area Network (WAN) that can span continents.
RDMA over a WAN allows some very useful capabilities that can increase the overall power of a clustered computer system. It can provide remote collaboration with a remote file system allowing access as though it were local, enabling apparent real-time collaboration. RDMA also allows very efficient file transfer over a WAN. This direct data placement is accomplished with little impact on the processors on either end of the file transport. These features are very useful for working with large data files such as those common in many HPC applications. Storage at a Distance will not directly impact conventional client computing since these devices typically don’t have access to dedicated high-speed Internet connections. However with the growth of on-line (cloud) services the use of RDMA could accelerate many background processes within a given data center and between data centers. This could improve overall cloud performance and provide services such as fast backups and replications of data to provide data recovery. Thus Storage at a Distance could have a great impact on the overall performance and capabilities available over the Cloud.