Does EMC's DMX Measure Up?

EMC says its new Symmetrix retakes the high-end hardware lead. Not exactly UPDATED 2/7 9AM

February 7, 2003

7 Min Read
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Last June, EMC Corp. (NYSE: EMC) president and CEO Joe Tucci -- referring to the next-generation Symmetrix line -- promised that the company would return to its heritage of delivering "the fastest, baddest, meanest, biggest boxes on the planet" (see EMC Flashes Wall Street).

With the Symmetrix DMX, launched earlier this week, EMC believes it has reclaimed the pole position in the high-end enterprise storage. "There's nothing out there that's as fast as this," said Tucci in an interview with Byte and Switch on Monday (see EMC Soups Up Symm and our full Q&A with Tucci).

But has EMC really reclaimed the hardware mantle? Most industry observers and analysts agree the Symmetrix DMX family represents a major advance in performance, provides more flexible deployment options, and cuts costs by sharing common components with the midrange Clariion line. [Ed. note: Not to mention the fact that it makes the old Symmetrix 5.5 look even more like a rusty relic.] But DMX doesn't win hands-down across the board.

Let's take a point-by-point look at whether the Symmetrix 6 really is the fastest, meanest (which we'll take to mean pricing), and biggest storage system in the industry.

Fastest: On this, it appears EMC has made the biggest leap forward and has the most credible claims of thrashing its competitors. The centerpiece of the Symmetrix 6 kickoff was the DMX, the Direct Matrix Architecture, a point-to-point, non-blocking technology that EMC says can provide internal bandwidth of up to 64 GByte/s. That's 40 times faster than the PCI bus-based Symm 5.5 (rated at 1.6 GByte/s), and four times faster than the Hitachi Data Systems (HDS) Lightning 9980V, the previous performance leader in the space at 16 GByte/s total internal bandwidth."This architecture is a big breakthrough for us," said Dave Donatelli, EMC's EVP of platform operations, at the launch in New York this week. "We've removed the major bottleneck -- the internal bandwidth of the system."

Competitors, though, dispute that the DMX really offers substantially better performance. "Their claims of performance is adding up the sum of the parts," said Phil Townsend, HDS's senior director of product marketing. They say the more relevant figure -- and the real architectural bottleneck -- is that the cache memory access on DMX is 16 GByte/s (32 cache segments multiplied by 500 MByte/s for each interface).

Fine, says EMC: The DMX still whomps the tar out of the nearest competitor. Its 16-GByte/s cache bandwidth is still well over the 10.6-GByte/s cache bandwidth Hitachi claims for the 9980V (four cache regions times 2.65 GByte/s provided by the Hi-Star crossbar switching architecture).

Table 1: High-End Storage Performance Specifications

Hitachi Lightning 9970V

EMC Symmetrix DMX1000

Hitachi Lightning 9980V

EMC Symmetrix DMX2000

Data Bandwidth

16 x 332 MB/s = 5.3 GB/s

64 x 500 MB/s = 32 GB/s

32 x 332 MB/s = 10.6 GB/s

128 x 500 MB/s = 64 GB/s

Message Bandwidth

16 x 166 MB/s = 2.6 GB/s

16 x 200 MB/s = 3.2 GB/s

32 x 166 MB/s = 5.3 GB/s

32 x 200 MB/s = 6.4 GB/s

Cache Regions





Cache Bandwidth

2 x 2.65 GB/s = 5.3 GB/s

16 x 500 MB/s = 8 GB/s

4 x 2.65 GB/s = 10.6 GB/s

32 x 500 MB/s = 16 GB/s

Cache Size

32 GB

64 GB

64 GB

128 GB

Front-End Connectivity

48 2-Gbit/s FC

48 2-Gbit/s FC

64 2-Gbit/s FC

96 2-Gbit/s FC


8 166MHz MIPS8 200MHz MIPS

60 500MHz PowerPC

16 166MHz MIPS16 200MHz MIPS

116 500MHz PowerPC

Apart from this circular they-said/we-said quarrel, EMC's rivals bellyache that Hopkinton can't prove the DMX delivers superior performance, because EMC refuses to test its systems using industry-standard benchmarks."EMC claimed that the Symmetrix DMX non-blocking architecture 'delivered the world's highest performance,' yet it has failed to disclose any industry-standard benchmark results, such as those available from the Storage Performance Council, that would back this claim up," says David Scott, CEO of 3PARdata Inc., a startup that has developed a high-end utility storage array competitive with the Symmetrix and HDS Lightning (see 3PAR Claims Benchmark Title).

EMC's position is that the SPC-1 benchmark is meaningless, because it doesn't test "real-world performance." That said, EMC is the only major vendor that is not participating in the SPC. "Until EMC shows what the box can actually do on the SPC benchmark, there isn't any fair comparison that can be made," says IBM Corp. (NYSE: IBM) spokeswoman Sandra Dressel (see LSI Screams Past IBM, Sun and HP Fiddles With Cache).

Meanest: In terms of pricing, the DMX simply drops the Symm in line with the rest of the industry. The DMX 800 starts at a list price of $409,000, cutting the entry-level price point for the Symm by about a third. EMC says its entire family of storage is priced at between 4 cents and 8 cents per MByte.

This is clearly a good development for customers, and it makes the DMX all the more attractive to prospective buyers. But it also reveals that EMC recognizes the tables have turned -- and that it's unable to charge a significant premium over its competitors.

Biggest: Nope. At least, not yet. The DMX, in fact, drops the maximum number of disk spindles it can support from 384 in the Symmetrix 8000 to 288 in the DMX 2000. However, EMC notes that with parity RAID turned on, the DMX has greater usable capacity -- 36.8 TBytes -- than the Symm 8830, which offered 34 TBytes of usable capacity with mirroring turned on.Regardless, that's still about one-third the 128-TByte maximum HDS now claims for the Hitachi Lightning 9900V, which is also resold by Hewlett-Packard Co. (NYSE: HPQ) and Sun Microsystems Inc. (Nasdaq: SUNW) (see HDS Launches Preemptive Strike).

EMC responds to this fact in three ways: One, customers don't need that much storage today; two, once they do EMC will be there; and three, the performance of an HDS system loaded with 100-plus TBytes would drag significantly. EMC claims the DMX architecture has the ability to provide up to 2,048 drives in a single system, which the company says it will do at some point, if "customer demands dictate."

"There's no technical reason why we couldn't have built a larger one, but the DMX model capacities are aimed directly at customer requirements," says EMC spokesman A.J. Ragosta.

However, EMC's own marketing materials appear to contradict this position. The first customer win the company announced for the DMX -- General Mills Inc. -- is deploying 150 TBytes. That means it needs to install at least five DMX 2000 units. Qu'est que c'est? (See General Mills Upgrades to EMC DMX.)

On the other hand, it's true that most enterprises' requirements fall within that maximum 37-TByte range provided by the DMX. According to IDC, EMC customers averaged 12.1 TBytes per unit. Even HDS concedes that 30 TBytes pushes the upper limit of what its customers typically run in a single frame, though it claims a handful do require more.Other features: (This would be "baddest," we suppose) Meanwhile, the DMX currently has some notable gaps, including support for Ficon, the IBM protocol for mainframe connectivity over Fibre Channel. EMC says this will be available in the third quarter of 2003.

The lack of Ficon support could be a deal-breaker for some EMC shops, analysts say. "Many traditional Symmetrix customers operate mainframe and open system configurations, and our conversations with customers of this profile indicate some disappointment with EMC on this topic," writes RBC Capital Markets

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