EMC and Data Matrix Architecture - Storage Networking - EMC Symmetrix DMX

Computer Technology Review, Feb, 2003 by Christine Taylor Chudnow

EMC's Symmetrix used to rule the storage roost, and is still one of the top three high-end manufacturers of storage arrays. But EMC, which was famous for high prices and a take-no-prisoners approach to customer negotiations, was hit hard by competitors IBM and Hitachi Data Systems (HDS). The technology downturn hammered them, too. The premium-priced company did not significantly lower its market prices, but in fact offered deep discounts to customers after years of refusing to do so. With profit and stocks down, they were not drowning, but were treading water.

It looks like that has changed. EMC has introduced the Symmetrix DMX, which it developed on top of an entirely new architecture: Direct Matrix Architecture. With this new product, which is fully compatible with existing Symmetrix models, operating systems and software, EMC has staked its claim again on the high-end storage market. Its timing is good: Even though the numbers of high-end storage customers may be shrinking due to budget concerns, the actual dollars that corporations are feeding into high-end storage remain very high. For example, high-end storage buyers are acquiring smaller companies that relied on mid-ranged arrays. Now that the larger company is bringing that data into the fold, they must protect and store the new data according to the same policies as the old, i.e., on high-end storage arrays.

In addition to offering very high performance, the DMX machines are fairly priced for their high-end market, starting at around $400,000 and ranging upwards of $2 million. (Yes, that's a lot of money, but high-end storage customers expect this kind of price tag. That's not to say they like it, but they will spend it.)

Competitors predictably downplayed the announcement while simultaneously announcing product enhancements of their own. EMC's two major competitors in the high-end storage market are HDS and IBM. (EMC happily reported a General Mills customer win over HP, but HP's high-end storage boxes are Hitachi boxes, not Storage Works.) HDS announced that it has doubled its Lightning 9900 V series capacity to 148TB of raw capacity, and is increasing connectivity up to 64 Fibre Channel 2GB connections. IBM made related announcements around its Shark array (ESS Enterprise Storage Server) high-end storage system. Shark now supports the Storage Management Initiative formerly known as CIM/Bluefin, and will expand within the month to a 72.8 GB disk drive capacity. In the face of these competing announcements, how does Direct Matrix Architecture differ from the earlier Symmetrix line?

Direct Matrix Architecture

Although DMX is integrated with the earlier Symmetrix models, it does not retain Symmetrix's bus architecture, nor is switch-based like the HDS arrays. EMC describes its new architecture as a matrix, a high-speed interconnect made up of dedicated point-to-point connections combined with global cache and an independent messaging and control function. According to Steve Kenniston, senior analyst for Enterprise Storage Group, DMX is a nicely timed and very significant new storage technology. "This is a good technology refresh for EMC. For 10 years they hadn't found a whole lot new, and now at the very high end they have a box that will outperform anything on the planet." Another analyst also commented that DMX will correct EMC's market losses due to flagging technology. Toni Sacconaghi at brokerage firm Sanford Bernstein reported in a research note, "Given that EMC is now competitively priced and has similar market share as Hitachi (and to some extent IBM), we believe its recent share losses are mainly attributa ble to its lagging hardware performance." DMX seems situated to answer that problem.

EMC released an upgraded version of the Enginuity operating system to handle the DMX hardware, but reports that only 5 percent of the code is changed. Users can also use existing Symmetrix software such as EMC's ControlCenter, and other software vendor packages supporting the Symmetrix will work on the DMX line.

Some sources insist on calling DMX a switched array, but its internal architecture is not a traditional backplane switching environment. Barry Burke, EMC's director of Symmetrix Platform Operations, talked about the confusion. "In general, the requirement of a storage array is to switch, so in a way every storage array is one big giant switch. What we're talking about is the board that talks to the hosts and disk -- you can use a bus, you can use a switch or a bunch of switches. What we've done is eliminate those and replaced them with 128 private highways."

The matrix contains up to 128 point-to-point connections, each of which directly link each front-end channel director and back-end disk director to all global cache memory regions. This provides the channel and disk directors with high-speed, non-blocking parallel access to all global cache directors simultaneously, which nearly eliminates contention, latency and bandwidth constraints. Here are the numbers: EMC reports that each dedicated connection is capable of transporting data at 500 MB per second, resulting in a total data path bandwidth of 64 GB per second.