Although storage tiering in one form or another has been a method to boost storage efficiency for years, it has evolved into more than one type.
Jon Toigo, managing principal at Toigo Partners International, discussed this topic with Executive Editor Ellen O'Brien at TechTarget's Storage Decisions conference in New York, where he explained how traditional tiering has evolved to spur another type: sub-LUN tiering.
According to Toigo, hierarchical storage management was the basis for traditional storage tiering -- a simple method for migrating data after a specified amount of time to lower-performing storage in order to optimize the use of high-performing capacity. Fast-forward a few years, and it's now common to see arrays that include both flash and disk drives that are sold with a tiering feature built in. Toigo said virtualization software vendors are also getting into the tiering game by working with their hardware partners, citing VMware and EMC as an example.
"The problem is, when you run out of space on that rig, you have to stand up another one," said Toigo. That's one of the main issues with today's traditional tiering. But another option, sub-LUN tiering, interprets the tiering feature in a different way -- it automates the process by detecting data that has a high access rate and temporarily moving it to faster storage. When requests for the data drop off, it is moved back to the disk location where the original copy is stored.
"That way, what you're doing is you're achieving the equivalent of 1,900 disk drives moving in parallel, but you're doing it with a far fewer number and a couple of [solid-state drives] SSDs, which consumes a lot less energy," said Toigo.
To hear the full conversation comparing traditional and sub-LUN tiering, take a look at the video above.