As the myriad advantages of flash storage over older technologies become more widely known, flash has increasingly moved front and center into the storage strategies of most IT managers.
But in a recent commentary, consultant Logan G. Harbaugh noted that because “most enterprises have multiple types of data, each with different priorities that are dictated by the size of the data and the speed needed by the applications that access this data,” most IT systems “do not have a single, homogenous type of storage. Because few enterprises can afford to put every bit or byte of data on the fastest available flash storage, hybrid arrays that mix flash and hard disk drives are a staple in many data centers.”
In Harbaugh’s view, the advantage of hybrid storage arrays that they can “address differing priorities and the need to reduce costs by joining various types of storage. Increasingly, this includes linking not just flash and HDDs, but multiple tiers of flash, multiple tiers of HDDs, tape, object and cloud-based storage into a single, transparent virtual storage infrastructure that can maintain the effective performance of the entire storage system at the level appropriate for each type of data and application.”
The question, however, is which types of data can benefit from hybrid storage arrays?
For one thing, Harbaugh argues, there’s real-time, transaction-based big data. “Live data is typically active and persistent; databases or other applications using live data will be turning over the data regularly, as users run searches and track sales or other activities. . . (A)dministrators may want to designate some databases, partitions or volumes of data that should be kept together on a particular tier to ensure there are no delays as a portion of the data is migrated from a lower tier if it is inactive for a period of time.”
Next, there’s what he calls “typical file server data.” The usual data stored on a file server, which includes text, word processing, spreadsheets and presentations, seldom needs the speed of flash, he says.
Similarly, since streaming data is, by definition, predictable and sequential, it does not need the low-latency, random-access capabilities of flash.
Of course, the fact is that many factors can determine on which tier data should be kept, so designating the type of storage data should receive can be complex. The bottom line for Harbaugh, however, is that hybrid storage arrays can offer the speed and low latency of flash and the economy of HDDs, tape or cloud. “They are necessarily more complex than all-flash or all-HDD systems, but the flexibility and lower cost make them worth investigating.”