Storage Management Strategies for the CIO
This article can also be found in the Premium Editorial Download "Storage magazine: Comparing the top data backup packages."
Download it now to read this article plus other related content.
In terms of speeds and feeds, Symmetrix DMX is clearly an improvement over its predecessor. By moving from mirroring (RAID 0) to parity RAID, DMX has slightly more usable capacity than a Symm 8000 (37TB vs. 34TB), but uses fewer disk drives (288 vs. 384). Connectivity is up from 32 ports on the 8830 to 96 front-end ports on the DMX 2000. Last but not least, cache bandwidth improved dramatically. By switching from a bus to so-called matrix architecture, Symmetrix DMX got a 40X boost in aggregate cache bandwidth, up from 1.6GB/s to 64GB/s --compared to 15.9GB/s on Hitachi's 9980V array.
Or did it? EMC's claims to 64GB/s aggregate cache bandwidth (128 direct connections through cache at 500MB/s) is what Arun Taneja, an independent analyst in Hopkinton, MA, calls "a marketing spec number." "The more important number is 16GB/s"--the performance that a fully loaded DMX 2000, with its eight caches, can actually sustain (each with four regions, accessed simultaneously at 500MB/s),
Requires Free Membership to View
Taneja says. By way of comparison, HDS's 9980V has an effective internal cache bandwidth of 6.4GB/s.
On other fronts, DMX remains vulnerable to the HDS 9900 in terms of capacity, with only 37TBs, compared to the 9980V's 128TB. DMX is also missing a mirrored cache, although it does support a new error mitigation algorithm called Triple Modular Redundancy with Majority Voting. Only time will tell if this will satisfy users. "I'd hate to have a Florida situation," says Phil Townsend, HDS senior director of product marketing. "What happens then? A recount?"
This was first published in March 2003
Join the conversationComment
Share
Comments
Results
Contribute to the conversation