Software Defined Storage – Hype or the Future?

If you have a twitter account, or read any of VMware’s press releases, or any of the technical blogs, you have to know by now, VMware is back in the storage business with a vengeance.  As most of us will recall, the first rollout, their Virtual Storage Appliance, VSA, was less than exciting, so I have to admit when I first heard about vSan I was a little skeptical.  Of course over the past several months, we have watched things play out on social media with the competitors, arguments over software defined storage versus traditional hardware arrays, which begs the question, is Software Defined Storage all Hype, or is this the future of storage?

So as always, in the interests of full disclosure, I work for HP, who clearly has a dog in this fight, I have worked with VMware products for nearly ten years now, as a customer, a consultant, and in my current role speaking about VMware to customers, and in various public presentation forums as often as possible.  While I attempt to be unbiased, I do have some strong opinions on this.  That being said…

When I first touched VMware, I was a DBA/Systems Engineer at a Casino in Northern California.  We badly needed a lab environment to run some test updates in, and despite some begging and pleading, I was denied the opportunity to build the entire production environment in my test lab.  We debated going with workstations and building that way, but one of our managers had read about VMware, and wanted us to determine if we could use it for a lab, with the thought that we could virtualize some of our production servers.  Keep in mind this was in the early ESX 2 days, so things were pretty bare at that point, documentation was spotty, and management was nothing like we have today.  By the time we completed our analysis and were ready to go to production, ESX 3 was released and we were sold.  We were convinced that we would cut our physical infrastructure substantially, and we thought that servers would become a commodity.  While compute virtualization does reduce physical footprint, it does introduce additional challenges, and in most cases it simply changes the growth pattern, as infrastructure becomes easier to deploy, we experience virtual sprawl versus physical sprawl, which leads to growth of physical infrastructure.  Servers are far from a commodity today, server vendors are pushing harder to distinguish themselves and to go further, higher density, and give just a little bit more performance or value.  In the end, VMware’s compute virtualization just forced server vendors to take it to another level.

When VMware started talking about their idea of a vSan, I immediately started trying to find a way to get in on the early beta testing.  It was a compelling story, and I was eager to prove that VMware was going to fall short of my expectations again.  There is no way the leader in compute virtualizaiton can compete with storage manufacturers.  Besides, software defined storage was becoming fairly common in many environments, and something that is moving from test/dev into production environments, so the market was already pretty saturated.  As I started to research and test vSan for myself, as well as reading up on what the experts were saying about it, I was quite surprised.  This is a much different way of looking at software defined storage, especially where VMware is concerned.

At the end of the day there are a lot of choices out there from a software defined storage perspective.  The biggest difference is who is backing them.  When I was building my first home lab, and software defined storage was not really prime time, we used to play around with Openfiler and Freenas, which were great for home labs at the time.  They gave us iSCSI storage so we could test and demo, but I have only met a few customers using it for production, and they usually were asking me to help them get something with support to replace it.  The main difference with vSan, and the other commercially supported software defined storage implementations are the features.  The reality is that no matter what you choose, far more important than which is the best solution, is having enterprise level support.  The important thing is to look at the features, put aside all the hype, and decide what makes sense for your environment.

I don’t think we will see the end of traditional storage anytime soon, if ever, although I think in many environments, we will continue to see high availability move into the application layer and shared storage will become less of an issue, think Openstack.  I do think though that most of us will agree that software defined storage is the future, for now, so it is up to you, the consumer to decide what features make sense, and what vendor can support your environment for the term of the contract.

Software Defined Storage – Hype or the Future?


Going through the VMware storage options I would be remiss if I did not talk about VSAN.  VSAN is simply VMware’s next way of helping to further improve the Software Defined Datacenter.  To begin with though, it is important to understand a little about what VMware is trying to accomplish. 2 years ago, on gigaom, an interesting article came through on VMware’s slow and steady attack on storage. This was following the release of their less than stellar Virtual Storage Appliance, VSA. At the time I took exception with this. Of course VMware would never want to get into the storage business, they are a software company. Then came VSAN.

I still do not believe VMware intends to completely own the storage market, but they are certainly changing the game. Now I work for HP, and I remember when server virtualization started to take off, we thought the server was going to become irrelevant, we would just use some cheap whitebox server. Fortunately we at HP realized that we had to step up our game. As usual the server engineering team worked with our alliance partners and built even better products designed around virtualization to give higher virtualization density, and higher performance. I equate this latest storage product to the same thing. It will certainly capture certain market segments, but it is not a threat to the core storage business of the larger storage vendors.

With that said, just what is VSAN? The concept behind VSAN is actually an old one come again. We have been doing scale out object storage for some time in this industry. VSAN simply moves this into the hypervisor stack. The requirements are pretty simple, you need a minimum of 3 host servers running vSphere 5.5 each with an SSD and at least one SAS or SATA drive, HDD. The requirements are well documented so I don’t want to get into those details, but this is enough to get started.

Conceptually, the SSD becomes a cache to accelerate the reads and writes to the drives. The HDDs are used for storage, and replicas are kept based on the rules, generally at least 2 copies of the data on separate hosts.

The setup is pretty simple, and there are hands on labs available online with VMware. It is also quite simple to setup using VMware Workstation running vSphere 5.5 for labs.

This scales currently, in Beta v1, to 8 hosts, so this is not going to be a massive system, more of an SMB environment or a lab system. It also introduces some interesting challenges on the server and network side. On the server, there is pretty limited official support since the raid controller has to enable pass through. There is no raid since this is an object store, data protection is accomplished through multiple copies of the data. On the network side, this is challenging because we are copying data between hosts to retain consistancy. This generally, in my mind, means that the era of running VMware on 1GbE networks is probably nearing an end.

At the end of the day, VMware has a number of use cases. This is a Beta v1 product, I am nervous about running it in production just yet. Many of their use cases are around high performance workloads, VDI for example, where user experience can make or break a project. I do think that this is an exceptional way of creating shared storage in a lab, and gives us many new ways to work in a lab environment.

As to the future of VMware storage, traditional storage, and our industry, I think this is the beginning of the next big thing. I will be discussing HP’s own software defined storage soon, as well as our traditional storage platforms in a VMware context. I don’t see VSAN as a threat, but rather as a call to action on our part to make our products better and continue to innovate. I will personally use VSAN in my lab along side HP StoreVirtual, different use cases, and fun to test.