As health IT managers consider the best way to take advantage of flash storage options, perhaps one of the biggest challenges they face is determining how to balance the opportunities flash offers with the ongoing performance of current hard disk (HDD) systems.
Writing recently at Tech Target, Logan Harbaugh, an IT consultant, says for many enterprises the answer may be to split the difference and build a hybrid storage system that will enable users to direct their most important and frequently data to SSD, or flash, while the rest can be stored on existing HDD systems. Although hybrid flash arrays are more complex to manage than all-flash arrays or all-HDD systems, Harbaugh says the flexibility and lower cost make them worth considering.
“While SSDs have obvious performance advantages, including better throughput and IOPS, they offer some less obvious benefits, as well,” Harbaugh argues. “Not only do they provide lower power consumption at idle, but they have the ability to go from idle to active in microseconds, while spun-down hard drives may take seconds to go from spin-down mode to active.”
The key to a successful hybrid system, Harbaugh explains, is to determine how to distribute data among storage options based on importance and frequency of use. “Tiering or automatic data migration will generally keep the most active data in the fastest available tiers,” he explains, “although data sets can be manually designated to run on specific storage. You might want to do that, for instance, if you want to always keep database indices in an all-flash partition. By moving the most-used data to the fastest storage, any data in use will get the best performance available.”
Harbaugh notes that the actual percentages will vary, but keeping the 20 percent most active data in flash requires only 20 percent or less of the total storage capacity to be flash. Because flash is fast enough to support compression and deduplication without performance degradation, users can gain a two and a half to six-time reduction in the amount of flash needed to hold 20% of the total data.