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Primer Series: Hyper-Converged Infrastructure

This article is part of our WWT Primer Series, a collection of content focused on the fundamental understanding of complex technologies and solutions.

June 9, 2020 6 minute read

Have you ever sat in a meeting and the conversation turns to a technology with which you are unfamiliar? Suddenly, a bunch of acronyms are being thrown around. You have no idea what they mean, while everyone else is nodding their heads and seems to know exactly what is being discussed.

We’ve all been there, and to help our valued customers, we've decided to write a series of 'primer articles' to give the reader basic information on various products and technologies. This article is going to cover the basics of hyper-converged infrastructure (HCI).

The long road to HCI

The evolution of the data center has gone through several iterations of technology. We've seen mainframes come and go (at least as a default option for new projects), the rise and fall of RISC-based server architecture, the x86 architecture introduction (servers) and the resulting physical server sprawl, centralized storage with virtualization (very much alive today) and now HCI.

We won't get into the world of mainframes or RISC-based architecture, but there's plenty of information on Wikipedia covering the topics if you have issues falling asleep at night. I know it seems improbable, but there once was a time where virtualization of servers (as we know it today) wasn't a thing and this caused many problems. The list is too long to go through but here are a few major ones: 

  • Each new application was typically a new physical server.
  • Poor resource utilization across servers.
  • High power and cooling bills due to server sprawl.
  • Low ratio of administrators per server.

Skipping ahead a little where virtualization became mainstream, we have centralized storage arrays with x86 virtualization hosts. This is still the default model for most organizations today in the form of a converged infrastructure (CI). This model gives centralized storage management and centralized compute management through the virtualization layer. For the most part, this addressed some of the issues found above, however, while the technologies have evolved significantly, there are still challenges around this new model:

  • Large initial purchases to grow into leading to bad return on investments (ROI).
  • Specialized skill sets for storage management.
  • Challenging process to upgrade the software and firmware on both the storage and compute.
  • Slow provisioning of resources and long workflows.

What is HCI?

So what is hyper-converged infrastructure? HCI takes the traditional x86 servers that are used as virtualization hosts and instead of having external storage presented through dedicated storage arrays like in the CI model, the storage is local to the hosts. The magic comes from the software layered between the host and the storage that virtualizes the local disk drives into a high performing, redundant, single target storage pool. This is often referred to as the software defined storage layer (SDS). 

One big difference between the HCI appliances and the build-your-own models is that the hardware has been pre-validated and tested by the software vendor. This essentially eliminates the worry of driver and firmware compatibility during upgrades and letting the software vendors ensure everything has been tested prior to the general availability release of subsequent upgrades.

Hyper-converged infrastructure
Hyper-converged infrastructure

The concept of HCI has been around for a long time. We used to have newspapers delivered to us, separate alarm clocks on the night stand and vehicle dashboard mounted GPS devices. Some people still have some of these individual devices, however, all of these are now "hyper-converged" into our smart phone. Ever have that math teacher ask, "are you going to carry around a calculator in your pocket all the time?" Well the answer to this is now yes — it is a software calculator running on a smart phone. The concept is the same in this instance, except the targets are data center technologies.

HCI allows customers to start with enough hosts to meet initial requirements and grow incrementally as new projects start consuming resources. This model allows customers to run leaner data centers and get better ROI on hardware utilization as well as bring in additional redundancy. It becomes a single place to manage both compute and storage resources for quick provisioning and monitoring.

Incremental growth
Incremental growth

Benefits of HCI

There are several benefits organizations can realize by embracing HCI. Below is a short list of some of the most valuable and touted aspects possible with the proper implementation of HCI.

  • Ease of Scalability - Purchase appropriate resources for what you need today or in the near future.
  • Storage Optimization - The intelligent software layer is purpose built with virtualization in mind due to the tight coupling of storage and compute resources, allowing the software to understand the environment from the top to the bottom.
  • Interoperability Pre-Validation - The hardware sold with the HCI nodes have been pre-validated by the specific vendor to work optimally.
  • 80/20 Rule (Pareto's Principle) - 80 percent of the time, administrators are keeping the lights on and 20 percent of the time doing innovative work. Simplify the data center and allow administrators to focus on more innovative activities by offloading mundane upgrade and compatibility checks to the vendors.

Other terms

As you sit in the meeting, other terms thrown may be thrown around during the HCI discussion. Below is a brief description of other things you may hear:

  • HCI sounds an awful lot like ACI when said quickly. Do not confuse the two as they are two very different technologies.
  • SDS - Software Defined Storage: This is the intelligent software layer. Note that it's possible to do SDS without HCI but you cannot do HCI without SDS. See the third bullet point under benefits above.
  • CVM - Controller Virtual Machine: This virtual machine is not included in all HCI solutions, however, it is the virtual machine or service that runs the vendor specific software which at a minimum includes the virtualization of the physical storage and local management interface.
  • Vendors typically included in the conversation: VMware vSAN, Nutanix, Dell EMC VxRail, Cisco HyperFlex and HPE SimpliVity.

Learn more

Interested in learning more? Please take a look at our main HCI page for a wealth of information and reach out to your WWT account team to schedule a briefing, workshop or proof of concept in the ATC.

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