Flash consumption by the enterprise data center is typically done as a response to a specific performance problem. The flash purchase that often results are typically either an all-new flash array or it is added to an existing array. The hybrid and all-flash vendors have made a mark on the industry, mostly because the legacy storage array vendors were slow to provide appropriate data services and attractive pricing with their flash add-ons.
Dell may be an exception. They have long had a robust set of data services in their Compellent line of arrays that allowed for the automatic migration of data from faster tiers of storage to slower, and more cost effective, ones. As we discussed in our lab report and webinar last year, Dell enhanced their Compellent storage software to specifically support flash storage and they altered the way that their data migration technology operated so it better took advantage of flash storage.
The result is that while Dell offers a very compelling flash offering, very few of Dell’s customers (less than 5%) actually use all-flash. This is despite the fact that in revenue dollars Dell sells more flash storage than hard disk storage in its arrays. The logical conclusion is that Dell’s customers are counting on Dell’s Data Progression technology to optimize the use of their flash investment.
Another key difference is that Dell’s data progression technology is based on tiering instead of caching. This means that data is less temporal and that the tiers don’t necessarily over-react to sudden bursts of activity. In Dell’s case, all data is written to a small but high performance tier of SLC flash first, then as it settles is moved to an MLC tier and then finally to an HDD tier. Of course Dell offers a flash only option that stops short of the HDD migration, but according to Dell most of their customers opt for the budget saving attributes of hard disk.
While the advantages of tiering vs. caching is beyond the scope of a trade show briefing note, it is something that StorageSwiss will be covering in more detail in the future. Dell was the second vendor at the Flash Memory Summit that was not hiding the fact that they had a hybrid offering. The way that Dell moves data through its stack of storage media types is logical and cost effective and something worth considering as storage planners continue to try to solve performance problems.