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Dell's latest update to the Compellent Storage Center includes a novel approach to tiered SSDs, but it comes with caveats
The high speed of flash storage often makes it easy to justify its high price. But with Dell's new approach to flash tiering, that justification may no longer be necessary. Though the latest release of Dell's Compellent Storage Center includes new hardware goodies such as a very high-density 3.5-inch SAS enclosure and a raft of updates to the array's management and host integration software, the really big news is support for automated tiering between write-optimized SLC (single-layer cell) SSDs and read-optimized MLC (multilayer cell) SSDs.
The Compellent system could already automate tiering between expensive, low-capacity SLC SSDs and spinning disk. However, this new blend of the two predominant SSD techs allows Dell to claim it can deliver an all-flash solution for the price of disk. Using list price as a comparison, the same money that you might have spent on a Compellent array with 72 146GB 15,000-rpm SAS disks (roughly $197K) will now buy you a similarly licensed array with six 400GB write-optimized SLC SSDs and six 1.6TB read-optimized MLC SSDs (about $182K).
[ Also reviewed on InfoWorld: HP 3PAR conjures powerful storage magic | Get the latest practical info and news with Paul Venezia's The Deep End blog and InfoWorld's Data Center newsletter. ]
Even better, that pure SSD configuration can deliver three times the transactional performance (using a TPC-C benchmark), 85 percent less latency, and 15 percent more capacity while consuming 50 percent less power and rack space than its disk-based counterpart. In other words, if you have the right balance of performance and capacity requirements to effectively leverage it, this innovation could save you a wad of cash, deliver a huge performance windfall, or both.
Dell's novel approach to tiering does come with a catch. However, understanding this gotcha and its potential effects in the field requires a deeper understanding of SSDs in general, Dell's Data Progression tiering software in particular, and how Dell has leveraged both in this new release.
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