There's a trend in the datacenter called "converged storage" which is where you combine compute and storage into the same box. In our world Nutanix is probably the best known example of this, though we've written about others too (like Simplivity and Scale Computing).
I loved this idea when I first heard about it back in 2011. In fact Gabe and I gave Nutanix the "Best of Show" award in the desktop virtualization category at VMworld that year. (And they've won Best of Show or been a runner up in 2012 and 2013 too.
It seems that the rest of the world is catching on too, with more people talking about how converged storage is the next big thing. (Over 1m results in Google for ["converged storage"].) but I'm starting to wonder... is this a good thing or a bad thing?
One of the problems with converged storage is that you have to buy your compute and storage at the same time. So it's only really useful for greenfield projects. That hasn't really bothered me though since I focus on VDI and most VDI projects are new. (Or at least they're not reusing existing storage which is not tuned for desktops.) So my wondering whether converged storage makes sense is not a greenfield thing.
Rather, I'm wondering how smart it is to hitch your storage purchases to your compute (and vice-versa). Back in 2011 this was cool because it meant we could do all sorts of "special" things because the compute had certain guarantees about the storage and the storage had certain guarantees about the compute. But now there are literally dozens of storage vendors providing features that were only previously available on converged platforms. So in today's world do we want to lock the two of these together? It seems like the exact opposite of the whole modular / flexible promise of virtualization.
With a converged system, if I want to buy more storage, I have to buy more compute. It's like cable TV bundling or record labels forcing me to buy a whole album even though I only like the one song.
The original premise was that converged systems were easier to configure and performance was more predictable, but again, today there are so many storage vendors and many of them talk about automatic storage and no management. I wonder truly how much time the converged systems actually save me. What, I can't hook into a SAN on my own?
The other problem with the converged systems is that I'm now at the mercy of the vendor as to whether they'll let me pop the lid off the thing and install my own add-ons. They claim they need to do that to guarantee performance that and people don't want the complexity of the options, but if you can't figure out how to insert a GPU card then you shouldn't be allowed to touch a VDI.
So how have the converged storage vendors addressed this? By creating "families" of products with different options for CPU, memory, and storage.
Nutanix now has 11 different models, 9 different storage options, and 27 different processor + memory configurations. For example their NX-6000 series alone has 6 different processor options with three storage size options. Then specific combinations of those have 32, 64, 128, 256, and/or 512GB of memory options. So I have 14 different possible options just within the 6000 series alone, and that's one of four different product series they offer!
So what exactly am I getting with convergence besides some crazy Beautiful Mind type purchasing process?
Can converged systems really offer advantages that I can't get by buying whatever computer and storage I want as separate entities?