Tuesday, March 2, 2010


Early in the last decade if you were making a storage purchasing decision you likely would have been frustrated with sales presentations, analyst reviews and industry news about storage virtualization to the point that you’d rather purchase ANY product that didn’t have this mysterious capability. Of course, the uncertainty continues today, although the hype has died down. Unfortunately, another buzz phrase has cropped up to befuddle the marketplace – automated storage tiering (ATS).

I’m watching this unfold as I transition from end-user to peddler of shared data storage and there’s clear indication from several recent blog posts and tweet threads that ATS, as an idea, is getting abused much like storage virtualization has been for years.


Why is this happening? If you consider that all suppliers sell to their strengths then it’s no wonder this happens. You’ll generally have a leader or two who develop a conceptual feature into a real working product and start to pull in some mindshare (and hopefully for them, market share as well). When a feature or function starts to gain traction, you’ll find that folks on the supply side will generally fall into one of two camps; “We have that too” or “You don’t want that” and the debate rages from there.

The root of confusion lays within the “Me too!” crowd because, well, they may not actually HAVE it, but they have something close enough that they can fudge a little and get away with it. This feeds the “You don’t need it” side with the fuel of uncertainty with which they’ll try to capitalize on customer frustration.


A big part of the confusion around ATS is around the role of SSD as a tier of storage. Since SSD acts like disk but performs like traditional storage cache it doesn’t fit neatly into either category. For example, many (possibly all, I don’t know for certain) disk array systems will by-pass write cache for SSD bound blocks.

Does that now make SSD cache? Well, not according to the SNIA Technology Council’s storage dictionary. Cache is both temporary and performance enhancing. While SSD certainly improves performance, it is arguably not temporary storage.

Bottom line is that SSD can be used as a healthy part of your ATS solution. And it’s easy to see that eventually it will be a big part with traditional enterprise disk being squeezed out by SSD on the high end and big slow SATA/SAS disk on the low end. Who knows, maybe it will all be SSD at some point? Or bubble memory? Or quantum dots?

The point is, don’t let confusion around the future face of tiered storage scare you from adopting ATS today because you can reap real benefits here and now. Just make sure you’re choosing an architecture which will accommodate the changing landscape and you’ll be fine.

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