Don’t Mistake These Hyper-Converged Infrastructure Technologies as Mutually Exclusive

Jonathan McDonaldBy Jonathan McDonald

I have not posted many blogs recently as I’ve been in South Africa. I have however been hard at work on the latest release of VMware vSphere 6.0 Update 2 and VMware Virtual SAN 6.2. Some amazing features are included that will make life a lot easier and add some exciting new functionality to your hyper-converged infrastructure. I will not get into these features in this post, because I want to talk about one of the bigger non-technical questions that I get from customers and consultants alike. This is not one that is directly tied to the technology or architecture of the products. It is the idea that you can go into an environment and just do Virtual SAN, which from my experience is not true. I would love to know if your thoughts and experiences have shown you the same thing.

Let me first tell those of you who are unaware of Virtual SAN that I am not going to go into great depth about the technology. The key is that, as a platform, it is hyper-converged, meaning it is included with the ESXi hypervisor. This makes it radically simple to actually configure—and, more importantly, use—once it is up and running.

My hypothesis is that 80 to 90% of what you have to do to design for Virtual SAN focuses on the Virtualization design, and not so much on Virtual SAN.  This is not to say the Virtual SAN design is not important, but virtualization has to be integral to the design when you are building for it. To prove this, take a look at what the standard tasks are when creating the design for the environment:

  1. Hardware selection, racking, configuration of the physical hosts
  2. Selection and configuration of the physical network
  3. Software installation of the VMware ESXi hosts and VMware vCenter server
  4. Configuration of the ESXi hosts
    • Networking (For management traffic, and for VMware vSphere vMotion, at a minimum)
    • Disks
    • Features (VMware vSphere High Availability, VMware vSphere Distributed Resource Scheduler, VMware vSphere vMotion, at a minimum)
  5. Validation and testing of the configuration

If I add the Virtual SAN-specific tasks in, you have a holistic view of what is required in most greenfield configurations:

  1. Configuration of the Virtual SAN network
  2. Turning on Virtual SAN
  3. Creating new policies (optional, as the default is in place once configured)
  4. Testing Virtual SAN

As you can see, my first point shows that the majority of the work is actually virtualization and not Virtual SAN. In fact, as I write this, I am even more convinced of my hypothesis. The first three tasks alone are really the heavy hitters for time spent. As a consultant or architect, you need to focus on these tasks more than anything. Notice above where I mention “configure” in regards to Virtual SAN, and not installation; this is because it is already a hyper-converged element installed with ESXi. Once you get the environment up and running with ESXi hosts installed, Virtual SAN needs no further installation, simply configuration. You turn it on with a simple wizard, and, as long as you have focused on the supportability of the hardware and the underlying design, you will be up and running quickly. Virtual SAN is that easy.

Many of the arguments I get are interesting as well. Some of my favorites include:

  • “The customer has already selected hardware.”
  • “I don’t care about hardware.”
  • “Let’s just assume that the hardware is there.”
  • “They will be using existing hardware.”

My response is always that you should care a great deal about the hardware. In fact, this is by far the most important part of a Virtual SAN engagement. With Virtual SAN, if the hardware is not on the VMware compatibility list, then it is not supported. By not caring about hardware, you risk data loss and the loss of all VMware support.

If the hardware is already chosen, you should ensure that the hardware being proposed, added, or assumed as in place is proper. Get the bill of materials or the quote, and go over it line-by-line if that’s what’s needed to ensure that it is all supported.

Although the hardware selection is slightly stricter than with an average design, it is much the same as any traditional virtualization engagement in how you come to the situation. Virtual SAN Ready nodes are a great approach and make this much quicker and simpler, as they offer a variety of pre-configured hardware to meet the needs of Virtual SAN. Along with the Virtual SAN TCO Calculator it makes the painful process of hardware selection a lot easier.

Another argument I hear is “If I am just doing Virtual SAN, that is not enough time.” Yes, it is. It really, really is. I have been a part of multiple engagements for which the first five tasks above are already completely done. All we have to do is come in and turn on Virtual SAN. In Virtual SAN 6.2, this is made really easy with the new wizard:

JMcDonald_Configure VSAN

Even with the inevitable network issues (not lying here; every single time there is a problem with networking), environmental validation, performance testing, failure testing, testing virtual machine creation workflows, I have never seen it take more than a week to do this piece for a single cluster regardless of size of configuration. In many cases, after three days, everything is up and running and it is purely customer validation that is taking place. As a consultant or architect, don’t be afraid of the questions customers ask in regards to performance and failures. Virtual SAN provides mechanisms to easily test the environment as well as see as what “normal” is.

Here are two other arguments I hear frequently:

  • “We have never done this before.”
  • “We don’t have the skillset.”

These claims are probably not 100% accurate. If you have used VMware, or you are a VMware administrator, you are probably aware of the majority of what you have to do here. For Virtual SAN, specifically, this is where the knowledge needs to be grown. I suggest a training, or a review of VMworld presentations for Virtual SAN, to get familiar with this piece of technology and its related terminology. VMware offers training that will get you up to speed on hyper-converged infrastructure technologies, and the new features of VMware vSphere 6.0 Update Manager 2 and Virtual SAN 6.2.

For more information about free learnings, check out the courses below:

In addition, most of the best practices you will see are not unfamiliar since they are vCenter- or ESXi-related. Virtual SAN Health gives an amazing overview that is frequently refreshed, so any issues you may be seeing are reported here; this also takes a lot of the guess work out of the configuration tasks as you can see from the screenshot below, as many, if not all of, the common misconfigurations are shown.

JMcDonald_VSAN Health

In any case, I hope I have made the argument that Virtual SAN is mostly a virtualization design that just doesn’t use traditional SANs for storage.  Hyper-converged infrastructure is truly bringing change to many customers. This is, of course, just my opinion, and I will let you judge for yourself.

Virtual SAN has quickly become one of my favorite new technologies that I have worked with in my time at VMware, and I am definitely passionate about people using it to change the way they do business. I hope this helps in any engagements that you are planning as well as to prioritize and give a new perspective to how infrastructure is being designed.

Jonathan McDonald is a Technical Solutions Architect for the Professional Services Engineering team. He currently specializes in developing architecture designs for core Virtualization, and Software-Defined Storage, as well as providing best practices for upgrading and health checks for vSphere environments