How caching and automated tiering increase SSD efficiencyDate: Apr 04, 2013
Experts tend to agree: Deciding which data should be stored on solid-state -- as well as when and for how long -- is a job best left to automated processes.
In this Storage Decisions video, Dennis Martin, president of the analyst firm Demartek, discusses how the roles of solid-state caching and automated tiering can improve data accessibility by using solid-state storage more efficiently.
"In caching, a caching controller identifies what's hot data, and it says, 'Hey, let's put the hot stuff on the SSD. Put a copy of it on the SSD,' so you don't alter the back end. You just say, 'Put a copy of this data on there, so next time I do a read, it's right there,'" Martin said. "Multiple applications can benefit from that, because it's just a cache, and it really doesn't care which IOs, which applications, are running. It does this warm-up, or ramp-up time… and what you end up getting is lower load on the back-end hard drives, because a lot of this stuff is being cached up front."
He noted that flash controllers can take care of wear-leveling in SSDs, helping to prolong the useful lives of the drives used in a storage system. But he noted that this level of coordination requires automated tiering software that can continuously move data to where it needs to go.
"Think about this -- if you had one application, and you wanted to accelerate it, you would put all of its data on the SSD, and you're done. [If you] got all these apps, which ones should I put on the SSD? And then, once I make that decision, is that decision going to be good a month from now? … If you have more than one or two apps, you need some help with this, you need some automation to help with this, and that's where this tiering software comes in. It allows [data] to be moved around and does it for you automatically."
Martin also said that as SSDs are implemented, Demartek testing found that while storage efficiency improved, CPU utilization also increased because more work can get done while using solid-state technology.