A Newbie’s Introduction to vSAN

If you read my introduction post, you’ll know that my initial area of focus during my first few months in VMware was vSAN.

For someone who had no prior knowledge of IT infrastructures, learning about vSAN or even just about VMware’s technologies took me awhile. I wouldn’t say that the learning curve is extremely steep, but it is truly a whole new world to me.

Hence, today’s blog post shall be dedicated to this amazing technology that has kept me company since the beginning of my career. Hopefully it’ll be useful for people who do not understand what vSAN or Hyper-converged Infrastructure is.

First things first.

What exactly is a Hyper-converged Infrastructure and what is the difference between that and vSAN?

In essence, a Hyper-converged Infrastructure (HCI) is a combination of compute, storage and networking in a single system. This eliminates physical silos existing in traditional 3-tiered architectures where storage becomes increasingly costly and complex to provision and manage. With HCI, every aspect runs as a software in the hypervisor layer.

VMware’s HCI solution is made up of 3 separate components:

  1. vSphere (Software Defined Compute solution)
  2. vSAN (Software Defined Storage solution) 
  3. vCenter (Unified management tool that manages vSphere + vSAN)

Screenshot 2019-02-25 at 1.42.31 AM.pngVMware’s HCI Solution | Source

Hence, vSAN is a part of VMware’s HCI solution.

vSAN is a distributed storage platform where the hardware underneath it are servers that can double up as both storage and compute. It basically adopts the the same approach as what VMware did with the compute infrastructure, vSphere, where it abstracts and decouples the storage away from the hardware.

In the past, storage vendors sold their hardware together with their propriety software. This created a lot of inconveniences for organisations when it came to scalability. They had to purchase hardware from that specific vendor and were not able to use commodity hardware.

Today, you are able to buy any industry-standard x86 servers from whatever vendors you prefer, as long as it is vSAN compatible. Gone were the days where vendor lock-in limited business’ ability to be agile. There are a ton of options- VMware has partnerships with almost all the major storage vendors out there (e.g. Dell EMC, HPE, Cisco…etc.). This is what it means to be truly hardware agnostic.

Furthermore, what’s amazing is that you now have the flexibility to decide what to configure depending on your requirements, e.g. you can could have an All-Flash configuration where you prioritise performance or you could opt for the Hybrid flavour where performance is not key but cost is. Scaling becomes very flexible and cost-efficient because with a software defined storage solution like vSAN, you are able to scale-up (adding more disks) or scale-out (adding more nodes).

Unlike the traditional ways where you typically buy new expensive storage arrays or controllers to cater for unexpected growth, with vSAN you can buy whatever you need now and in the future when it is necessary, you are able to scale easily.

The approach towards scalability and growth is starting to shift tremendously from storage being under or over-utilised towards one where storage can grow alongside with your business.

So how does it work?

Allow me to simplify this for you. I’m not the best at story-telling nor creating analogies but I’ll give it a try.

Imagine you and your friends needed to build something out of bricks. It just so happens that you have several baskets of colourful bricks- blue, red, yellow, green… you name it, you have it. You then proceed to take out all these bricks inside the baskets and pool them together. To you, these are just bricks. You do not care if they are yellow, blue, red or whatever colour. They’re just bricks to you.

You then bring all these bricks together and stack them into one shared pile. Now, your friends are able to swing by your house and grab whatever amount of bricks they need to do their task.

That’s vSAN for you.

Image result for VSAN

vSAN’s Architecture | Source

vSAN works by abstracting and pooling all the locally attached disks (SSDs/HDDs) in your x86 servers and views them as nothing but just capacity. It then aggregates them into a single shared datastore where all your applications and virtual machines would run on top of it.

For those who are wondering, you can run almost everything and anything on vSAN. vSAN can run all your virtualised workloads, be it VDIs, SQL Apps/DB, Oracle…etc or your mission-critical applications. How amazing is that? Basically, whatever works on vSphere, can surely run on vSAN.

What about LUNs and RAID concepts? Where does all these come into play?

Well, let’s just say that the concept of RAID in the traditional way is not entirely applicable when it comes to a software-defined storage solution like vSAN. In vSAN, if you needed to create protection or performance profiles, you can easily do so via “Storage Policies”.

Image result for storage policies vmware vsan 6.7
Creating Storage Policies | Source

When I say easy, it truly is easy. It only requires a few clicks of a button just to attach or change a policy. These policies can be attached to a virtual machine or at a more defined level such as the VMDK (virtual machine disk).

It is because of this that the need for complicated constructs like LUNs have been eliminated.

I’ll share more about storage policies in my future posts.

To Conclude

The value of vSAN really revolves around saving cost and driving simplicity (more about this in my future posts) and efficiency. After all, isn’t almost every organisation’s challenge all about cost and efficiency?

On a personal note, I’ve learnt a lot more about vSAN in the past year or so. Having an area of focus was extremely helpful for me to have time to truly understand what the product does, how it works and the underlying value and reason for its existence. vSAN is definitely a great place to start if you are new to VMware’s virtualisation technologies.

P.S. In the past, when I thought about “storage”, I’ve never thought about anything else other than my blue-coloured Western Digital 1TB HDD that stores all my crap in it. What a huge step I’ve taken, haha.

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