Everybody and their dog knows about it. 10.000+ end users asked to test its beta version. And it will be publicly available in a few days.
Yes, I’m talking about VMware VSAN.
Now, the question is: “Will it radically change the way you look at your storage infrastructure?”.
Short answer is “I hope so!”, but there is something more to say.
VMware VSAN
VSAN software is capable of using local storage resources, disks and Flash memory installed in each server of your cluster, to build a distributed storage pool. This actually materializes data stores for your VMs and eliminates the need of a shared storage infrastructure. It has almost all the characteristics you take for granted in a modern enterprise storage system and it can easily become a good choice for building new infrastructures from scratch. (you can find many technical articles on VMware VSAN on Duncan Epping’s blog)
This way of designing storage in virtualized environments has many advantages when compared to traditional storage approaches, ranging from lower purchasing costs to a total separation between hardware and software. Obviously cost savings is only the first step, immediately followed by ease of management and speed as the other two key factors.
In this particular case, integration between VSAN and vCenter is total, but there is a flip side too.
1.0 is still 1.0
From my point of view, adopting VSAN 1.0 in critical environments is just a leap of faith in VMware at the moment. 
The product has many interesting aspects but also shows a certain grade of immaturity and the flaws of a 1.0 product. I have no doubts that future releases will bring improvements, but it is much harder to say how and when.
As I mentioned before, VSAN is deeply integrated into the VMware stack, so integrated it uses ESXi snapshots (not the kind of snapshot you can rely on, indeed). This is just an example, but the list gets longer when compared to products already available on the market: no compression or deduplication, rigid configurations, no multi hypervisor support and so on.
Alternatives?
Limits and constraints of VMware VSAN don’t change the scenario: business demands agility and savings and the software-defined approach is fundamental to drive down costs and ease management.
VMWare doesn’t have a unique product and many others are working on similar solutions. The list is getting longer day after day and there are products for each market segment now. Even primary vendors like EMC (with ScaleIO) or HP (with StoreVirtual VSA, my report here) have notable solutions but, as usual, the most brilliant and innovative solutions come from startups.
VSA or Hyper-converged?
This is a hamlet-type question indeed, “should I go with an integrated stack or not?” and the answer is always the same: it depends!
In any case, the solution can be chosen based on your needs. Hyper-converged infrastructures like Nutanix or Simplivity can guarantee the end-to-end solution while products like Maxta MxSP or Atlantis USX give maximum freedom in terms of design and implementation. The latter can also be particularly interesting when you want to implement the VSA on an existing traditional SAN.
Why it matters
VMware VSAN is worth a try. The product isn’t perfect yet but, if you can overlook the limits of this 1.0 version, it is fast, perfectly integrated within your VMware infrastructure and transparent.
On the flip side, VSAN is a big lock-in and there are other solutions out there that could make you even happier.
VMware is officially becoming a storage player, which changes a lot of things (I wrote about this a couple of years ago). From now on it’s obvious that the first option for your Vmware infrastructure comes from VMware itself. They are cooperating and competing at the same time with almost all their storage (and networking) hardware partners now. Sound like Microsoft of the 90s?
Once again, storage is rapidly changing, is your strategy aligned?
