In our clubby storage-meets-virtualization world, few new products have generated as much excitement as VSAN: VMware’s Virtual SAN.
As part of the VMware PEX (Partner EXchange) keynotes this week, VMware’s new CTO Ben Fathi shared a fairly detailed “status update” on VSAN, ahead of general availability.
I thought I’d recap what Ben shared publicly — in case you weren’t at PEX, or maybe you’re just wondering what all the fuss might be about :)
This slide provides a good first-approximation of what VSAN does. It’s storage software that makes internally-attached server storage into a shared, protected storage pool.
Unlike other software-only storage solutions, it doesn’t suffer the inefficiencies and complexities associated with running in a dedicated VM: VSAN is fully integrated with the vSphere kernel and all that it implies — more on that later.
VMware is describing this architecture as "hypervisor-converged" -- and I think it's a useful distinction.
VSAN will be sold as a standalone product. As we’ll see, it has surprisingly good performance in its current form. It competes well on CAPEX, and does exceptionally well on OPEX thanks to its app-centric policy-based management model.
And — as everyone comments — it’s dead simple to install and operate.
Even the best software needs hardware to run on, and the VSAN approach is especially well-thought out. The goal here is to support maximal customer choice on servers, networks, flash drives, rotating rust, etc.
As this press release summarizes, VMware is building a VSAN-specific compatibility guide with a growing number of choices. For those that prefer a pre-integrated appliance approach, VMware is working with server partners to create VSAN-ready nodes.
The VSAN beta was first announced last August at VMworld, and it’s been amazingly successful. Close to 11,000 people have registered, with about half of them active in the VSAN beta community.
The lengthy and extensive beta means that VSAN 1.0 won’t be your typical 1.0 product — a lot of people have been beating on it for quite a while -- and obviously came away quite impressed. One survey showed that 95% of the beta participants are likely to recommend VSAN as a result.
Hopefully, I get to speak with the other 5% before long :)
The Scale And Performance
The VSAN beta was announced with 3 to 8 node support. Ben announced that the VSAN team had over-delivered, and VSAN would be at least 16 nodes at GA.
Just to put that in perspective, each VSAN node can support up to 35 disk drives (in addition to up to 5 SSD or PCI-e flash devices), so we’re talking about a potentially large config here. That’s a max of 560 spindles in a single VSAN cluster.
Ben also shared some preliminary “hero” performance numbers: 915K read-only IOPS using 4K blocks at 16 nodes. Note that this was done with < 10% of CPU resources being consumed. He also shared 465K “mixed” IOPS, but I don’t think he mentioned what the specific mix was :)
The first observation: these performance levels are in the range of top-shelf hybrid arrays, and approach a reasonable subset of all-flash performance. I also believe these performance levels will exceed the newer software-only storage solutions that run in their own VM.
The second is the usual caveat: as always, your own application performance testing is always the best :)
Simple To Install
Ben showed how just two clicks got VSAN up and running.
One of the clicks is to enable it (it goes out and inventories available hardware, assumes some defaults, and presents you with a ready-to-use storage pool). Storage-related views and tasks are simply integrated alongside other things the VM admin already does.
Or, as Ben put it "if you know vSphere, you know VSAN".
The New Management Model
One of the more important yet subtle things about VSAN is its management model — it’s not about “managing storage”, it’s about managing application service levels where storage plays a role.
Administrators use the pre-existing policies, or create their own. These templates are applied at provisioning time, and resources aren’t actually consumed until asked for.
This is in sharp contrast to the bottoms-up approach used in storage today; one where the storage admin has to pre-provision pools to be consumed.
VSAN will also monitor policy, and take steps to either adjust performance or protection if possible. Speaking as a storage guy, it’s going to take some time for us storage types to wrap our collective heads around just how different this approach is.
Works With Everything VMware
Being fully integrated with the vSphere kernel brings some notable advantages. One clear advantage is performance and efficiency — there’s no need to traverse multiple VMs just to do IO.
But a potentially bigger advantage is the integration with the vast VMware suite: snaps, replication, vMtion, vCOps, vCAC, SRM, etc. etc. For VMware customers, everything works as one would expect: no plug-ins, no extra work required, etc.
Availability? Pricing? Packaging?
Everyone at PEX was clamoring for specifics, but that wasn’t shared. Ben did confirm that VSAN would be GA during the current quarter.
BTW, there’s a VSAN webcast on March 6th if you’re interested :)
A heckuva channel promotion was announced as well: the top VSAN channel salesperson will receive a Tesla S as a prize.
No, second place prizes weren’t mentioned :)
The New Buyer
As I’ve mentioned before, there are more than a few storage professionals that are justifiably skeptical about software-only storage technologies such as VSAN. I am not unfamiliar with their perspective.
Not to be blunt, but VSAN isn’t designed for them.
VMware has built VSAN for a new kind of storage buyer — the virtualization or cloud architect — who sees storage evolving along very different lines.
As an example, the beta product supports a full suite of straightforward APIs right out of the box — just as you’d expect with a real software-defined storage product (tip ‘o the hat to @lamw for this one). It's not an afterthought -- it's integral to the product's value proposition and target audience.
So, What’s The Big Excitement?
As I mentioned, I haven’t seen people this excited about a new storage technology — ever. So it’s fair to ask — what’s all the fuss about?
I think it’s pretty simple. People who have worked with VMware technologies for a while realize that VMware has the potential to transform how things get done in IT. That’s a historical fact when it comes to server virtualization.
They see the same thing starting to happen in networking with NSX and software-defined networking. And, in the same vein, they see the ideas and concepts embodied in VSAN starting to do the same thing for software-defined storage.
Once you can fully abstract, pool and automate *all* resources, you’ve got the basis for a software-defined data center.
And that’s pretty exciting stuff to many of us …
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