Hyperconverged infrastructure (HCI) vs. custom datacenters: Pros and cons

If you're evaluating storage solutions for your datacenter, you may be trying to decide between a custom datacenter build and newer hyperconverged infrastructure (HCI) appliances. I recently had the opportunity to review an HCI appliance, and I was pleasantly surprised by many aspects.

What is an HCI appliance?

An HCI appliance is like a server rack or cabinet with everything you need to run a small datacenter or cloud. It contains one or more firewalls or gateways, multiple network switches, power backup, cooling, a storage solution, and blades for all your computer needs.

The cabinet comes preconfigured and internally cabled, so it's ready to be rolled into your datacenter, network closet, or your parents' garage. It is then plugged into a power source and network drop to provide a fully functioning datacenter appliance. Some HCI solutions can be chained together to work as one.

HCI appliances often come preinstalled with storage, network, node-management software, blade operating systems, and even container orchestration platforms (such as Red Hat OpenShift).

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HCI vs. custom datacenter: pros and cons

HCI appliances and custom datacenter builds have strengths that make them more suitable for certain environments. If you're comparing HCI to a custom datacenter build, the following information may help you decide which makes more sense for your organization and your specific wants, needs, and requirements.

Convenience and speed

HCI's most obvious benefit is convenience. For many years, I've participated in cluster builds, both physical hardware and virtual-machine based. My team's last bare-metal build, which has redundant firewalls, load balancers, multiple availability zones, high-speed redundant storage-area-network (SAN) storage, multiple routes in and out, and highly configurable blades, took over a year. This included the build's conception, planning, financials, ordering, and installation. The installation included cabling, redundancy cooling, redundant power sources, and everything else you might expect in an enterprise datacenter multi-cage (or multiple failure zone) cluster build.

The HCI environment I recently used took only a few weeks from start to finish. Once I had approval for the project, the appliance was ordered, delivered, installed, and up and running within three weeks. The only significant delay was the high-power cabling, which the existing cage was not equipped to handle, so the turnaround time could have been even shorter.

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Configurability

You get significant convenience with HCIs, but there is a natural tradeoff with configurability. With an HCI, you don't get all the configuration freedom you would have with a custom, ground-up build. You also pay more upfront for an HCI appliance. On the other hand, you don't pay the salaries of the highly technical experts you need for a custom build. You also don't have a long delay before you can use your hardware with an HCI.

The HCI appliance is also more opinionated than a custom build. This means that the HCI architecture team made some decisions about how your platform is built and configured. For example, with an OpenShift HCI, the architects may have chosen the number and size of the management nodes, the Ingress capabilities, which plug-and-play virtual networks are included, the platform version, update schedule, and more.

Whether this is a pro or a con is up to you. If your staff includes experts in these areas, you may not want to be locked into another team's architectural decisions. However, I suspect most organizations considering an HCI appliance will be happy to have experts making these decisions to make the entire system work well on day one.

Expansion and geographical limits

Another consideration is that each HCI appliance is independent of the others. They cannot span multiple cabinets, but they can be chained together to make multiple clusters work together as one unit.

While planning a datacenter solution built from HCI appliances, ask how many can be chained together and whether there are geographical limitations. You should also ask how they behave with workloads when they're connected and any other questions specific to your datacenter needs.

Software and support

The final aspect to consider when evaluating HCIs and custom datacenters is how the software and support model works. With HCI appliances that include the necessary management and computer platform software, updates are extremely smooth. Updating the firewall firmware, kernel, drivers, container runtimes, and everything else can (and should) be handled during one window. All the drivers and software have been tested together, and the upgrade and migration path has also been tested. This should provide very smooth and predictable maintenance upgrades.

With a custom datacenter, you must investigate every device and the full software stack for compatibility, order of operations, data migration, and more. Updates can go very wrong, and it's much harder to estimate the time to completion.

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Support for the HCI appliance is streamlined. You talk to one vendor that is responsible for the complete stack. They will direct your inquiry as needed and work closely with the teams handling support. For example, if you need additional support from the appliance hardware maker, the HCI vendor handles that interaction and chases down solutions for you.

With a custom datacenter build, you must contact and coordinate support with each vendor. Sometimes, a vendor might say they don't support your configuration. This means you have to figure out how to solve the problem yourself.

Conclusion

Hyperconverged infrastructure is neither a baby step into building datacenters nor a replacement for custom-built datacenters. Consider the advantages and disadvantages as they affect your organization and its requirements. Consider whether you can update node hardware, add GPUs, or expand storage and memory. Research any expansion and chaining limitations and whether you can chain to other geographical locations. Understand the upgrade cycle and the vendor's decisions around networking, redundancy, and disaster recovery.

You might be thinking, "these are the same questions we ask when building custom datacenters," and you're right. The problems and decisions are the same, but with an HCI, someone else has made well-educated decisions about them. Above all, HCI is an interesting and convenient new delivery mechanism for modular datacenters.

[ Check out Red Hat's Portfolio Architecture Center for a wide variety of reference architectures you can use. ]

This originally appeared on Hybrid Cloud How-tos and is republished with permission.