Just when you thought you had a handle on the various methods of data storage, a group of storage makers have developed yet another way to keep your company’s information stored and secure.
Pioneered by Sunnyvale, Calif.-based Network Appliance Inc. and Santa Clara, Calif.-based Intel Corporation, direct access file system (DAFS) is a protocol capable of performing remote direct memory access (RDMA) over various transport methods.
According to the DAFS Collaborative, chaired by NetApp and Intel and made up of approximately 85 companies, the protocol will enhance the performance, reliability and scalability of Web farm, e-commerce and database applications in data centre environments.
“It is a next-generation data centre interconnect,” said David Dale, industry evangelist with Network Appliance. “DAFS is designed as a file access protocol that specifically leverages this RDMA capability. It is also designed for data centre environments. What DAFS does is it accelerates the performance of the database by significantly reducing CPU overhead on the database server.”
According to Randy Kerns, senior partner with Evaluator Group in Denver, in order to understand DAFS, users must understand the issues with network attached storage (NAS). NAS, which consists of a specialized file server that connects to the network, has made almost no inroads into the enterprise data centre space due to concerns with performance and security.
“In the performance realm, people are looking for guaranteed response times with very high performance,” Kerns said. “What DAFS does is change the whole model to give a quantum leap in performance for doing transaction processing with databases. Now NAS (appliances) that are DAFS-enabled become incredibly viable in those market segments where it was questionable before.”
Kerns continued that NAS typically adds more elements and software programs to run storage file system requests over TCP/IP, which causes increases in overhead in the path. DAFS doesn’t require TCP/IP to run file system requests. The protocol can use any transport mechanism, such as Ethernet or ATM, and can perform these Remote DMA operations, which essentially transfer data between the device and application memory directly, and bypass all the moves between the system address space and the application. The result, Kerns said, is a phenomenal increase in performance.
Norman Hutchinson, an associate professor of computer science at the University of British Columbia in Vancouver, has been part of the DAFS Collaborative conducting research and designing prototypes of the DAFS specification.
“The various companies involved wanted to make sure that this didn’t become a proprietary kind of thing,” Hutchinson said. “They wanted to have reference implementation of the protocol both on the client side and the server side. That is what we are working on at UBC.”
Hutchinson noted that DAFS is still in its infancy and there are limitations in terms of security. The protocol is intended for very closed settings called local sharing environments whereby all file servers are clustered together.
“Essentially the machines involved in the DAFS cluster are exposing themselves to their peers because a client machine can write directly into a server machine’s memory,” he said. “That is a dangerous thing to do if you don’t trust the client. Exposure would be a problem.”
Already to market is the DAFS Database Accelerator from Network Appliance. The DAFS Database Accelerator uses virtual interface (VI) technology over a gigabit Ethernet interconnect and is designed to run on IBM DB2, Oracle 8i and 9i and Sybase 12.5 database releases.
“What it does is it brings the ease of use and low total cost of ownership…into the high-performance database area – those places where in the past you would have had to use fibre channel attached radar or something like that,” Net App’s Dale said. “This addresses those database installations where the thing you need most is as much CPU power as you can get to run more users or run more transactions.”
For more information on the DAFS Database Accelerator, visit Network Appliance at www.netapp.com. Find the DAFS Collaborative at www.dafscollaborative.org.
