No, this post isn't really about this version of RAID or that version of RAID, it's just a suggestion that -- before too long -- we might use this acronym to refer to a very different (yet intriguingly related) concept.
To Begin With
If all this storage stuff is new to you, don't fret. The idea is simple -- use multiple disk drives that can appear as one: bigger, faster and more reliable. In the storage world, the advent of RAID fundamentally changed the industry in a substantial manner.
Interesting note: if you'd like to see an interview from the DG engineers who built the first commercial RAID array (the CLARiiON), check this out. All of them are still at EMC :-)
During the video, the thought comes out that the advance was driven by two things: growth in the power of CPUs, and new IP -- in this case, the foundational Berkeley paper on RAID concepts.
Someone had to take the two, and come up with a viable product, so the video is interesting in a "Soul Of A New Machine" kind of way.
Remember this as we dig into this next section.
New Fundamental Enabling Technology
I think many people saw VPLEX as fundamental new enabling technology -- the ability to pool storage (and anything that uses it) at increasing distances. At least, that's what I've been trying to communicate here and here :-)
I make the point several times that this technology has the potential to change how we think about data centers -- how many do we need, what they do, etc.
Put differently, VPLEX and its unique distributed cache coherence technology creates the potential -- over time -- for an entirely new interpretation of RAID.
A Redundant Array of Inexpensive Datacenters
Data Center Thinking Today
Most data center thinking today is predicated on size and scale. The thinking is that -- the bigger the data center, the more efficient it might be.
However, in talking to customers, there are some problems with that sort of approach.
First, we're talking massive capital projects here that consume enormous amounts of money and time. In essence, they are large, risky bets on future requirements.
Second, as scale increases, so do challenges. Land. Power. Security. Environmental impact. Bandwidth. Zoning. Politics. Data centers -- at scale -- create second-order challenges.
Third, you'll usually want at least two for recovery purposes. RAID 1, anyone? :-) Unfortuantely, the dominant model is that the second site rarely gets used at its full potential, with a preponderance of expensive resources sitting around waiting for a disaster that hopefully never happens.
Fourth, things change. Business models change, politics change, customer demands change, technology changes, and so on. If anything, change is accelerating -- making those big data center bets even more problematic.
Data Center Thinking Tomorrow?
Imagine that data center resources can be pooled as if they were in the same physical location -- the fact that they may be in different locations isn't a concern of yours. How would that change things?
I can make an argument that data center strategies would fundamentally change in many cases, with a strong preference towards smaller, more nimble data centers -- federated together -- rather than big, humongous ones with their associated challenges.
Rather than a 1 primary + 1 failover approach, we'd see N+1 clusters of much smaller data centers with enough redundancy to handle one, or potentially two, failures -- and recover gracefully.
No need to make massive bets on giant data centers. No external constraints on power, cooling, zoning, network, etc. Better use of all available resources. Faster. More reliable.
And -- ultimately -- more flexible.
Is This A Pipe Dream?
Yes ... and no.
Pat Gelsinger and Brian Gallagher were pretty clear about the VPLEX roadmap at EMC World. If you believe them and their ability to deliver (and I do), it'll be here as promised. And if you saw the teleportation demos, you know what's coming down the road.
Metropolitan bandwidth has come way down in many markets, making the required network connectivity more attractive than it once was -- and I'd expect that trend would continue.
Not to mention that Atmos has been doing geographically distributed parity protection for a while :-)
So, What Do You Think?
If the technology lives up to the promise, and bandwidth prices continue to fall, will we see a preference for redundant arrays of inexpensive datacenters? Or will we continue to build larger and larger "single site" approaches?
It's an interesting discussion, to be sure :-)