The HCI Definition Obsession

The HCI Definition Obsession

Chris EvansCloud, Data Management, HCI, Opinion, Storage

NetApp recently announced that Cloud Volumes Service (CVS) will be available on-premises with NetApp HCI. Storage has come full circle, as ONTAP transitioned to a service in the public cloud and is now back on-premises as a private cloud. When NetApp introduced their concept of HCI, the industry pooh-poohed it as not conforming to a true definition of hyper-converged infrastructure. Have people simply misunderstood NetApp’s strategy?

A Word on Cloud Volumes Service

We’ve talked a lot on this blog about Cloud Volumes over the past few years, including just recently with a discussion on how cloud service providers (CSPs) should implement new technology.

CVS provides access to faster and more feature-rich file storage than is offered by CSP’s own native solutions. As part of the Data Fabric, NetApp is providing customers with the capability to move data from on-premises to public cloud infrastructure and vice-versa. This mobility is an important strategy in the way NetApp is evolving.

You can learn more on CVS in this great Tech Field Day video.

Eiki Hrafnsson talks Data Fabric and CVS

Born in the Cloud

What happens if you started in the public cloud and don’t have traditional NetApp storage infrastructure but want to get the same look and feel of CVS, but on-premises? You could buy an appliance, run ONTAP Select or now, run CVS on NetApp HCI.


CVS on HCI is implemented on top of the storage component of the HCI solution, namely SolidFire. The cloud volumes service runs as a VM, providing CVS services in the same way CVS works in public cloud. If you’re orchestrating application deployments in a hybrid environment, then having CVS on-premises means you can have the same look & feel, the same APIs and expect the same features as you do in public cloud.

I will add one caveat though; CVS is running in (one or more) virtual machines on the HCI platform. NetApp should explain to customers how features like resiliency work, in case of hardware failure. As a “cloud” service, the detail is something the service provider typically hides, but with HCI the customer is managing the hardware and so needs some guidance.

Public/Private Cloud

So what if we take a different view on NetApp’s strategy? If we think of NetApp HCI as merely a (composable) platform for applications and discard the HCI definition, does that change things?

I think it does. (NetApp) HCI is simply a distributed storage layer and a layer of compute that happen to be separately deployed. “converged” HCI merges these together in a single form factor.

Look across the industry and existing HCI vendors and you see, for example, Nutanix offering “storage only” nodes (isn’t this just SAN?). Datrium developing a split HCI architecture that uses shared and local storage. VMware vSAN allowing storage-only nodes (although they’re not recommended). HPE has even released something called dHCI – disaggregated HCI that scales storage and compute separately (I think I’ve heard of that before).


Here’s another example to consider. When AWS announced Outposts, did anyone ask if this was a real HCI solution? Outposts can be deployed either in “VMware mode” (which presumably uses vSAN) or AWS “native”. Is the storage component hyper-converged or does it run on dedicated storage nodes? Do we need to care?

Choices & Requirements

What we see from the industry is a range of choices. You can consolidate servers and storage into a single form factor. Alternatively, you can scale storage and compute independently (but with a single scalable storage layer). You can split capacity and performance into two tiers. Of course you could also go rack-scale. This is all about choice.

We should be driving our purchasing decisions based on requirements and the choices available to us in the market. Many enterprise customers, for example, may like the idea of removing traditional silos of compute, storage and networking, but don’t feel comfortable moving to fully converged HCI. NetApp HCI is giving potential customers another choice.

The Architect’s View

As we move to a hybrid computing world, ask yourself whether adhering to a strict but unofficial definition actually matters. Consider instead that NetApp might be building a hybrid cloud strategy that gives their customers a consistent operating environment, wherever they deploy. Remember NetApp also rolled out NKS (the NetApp Kubernetes Service) on-premises with the release of CVS on HCI.

Personally, I try to avoid thinking about HCI as a definition and focus on how the solution could be deployed and best exploited. After all, isn’t that what we’re all here for?

Disclaimer: NetApp is a customer of Brookend Ltd, but had no input into the creation of this blog post.

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