The advantages and disadvantages of hyperconvergence as a basis for decision-making: hyperconvergence in practice

vom 21.07.2020

16.07.2020 I by Henrik Hasenkamp and Ulrike Ostler

With hyperconvergent infrastructures, companies should be able to set up a consistently virtual, software-based data center in just a few minutes. Is it really that simple and when does it make sense?

Convergence simplifies the IT infrastructure: Various components are combined into one appliance and managed centrally. The individual elements are configured and combined with each other in a way that works best, often based on years of experience of the IT teams.

Often, convergent systems are the result of practical experience. As a highly specialized, pre-configured rack solution, for example, they are quickly ready for use, and additional components can be added relatively easily.

Hyper Converged Infrastructure (HCI) extends this concept to the entire infrastructure. Convergence now takes place via a complete virtualization of the IT architecture. In this process, the software that previously controlled the individual devices is being replaced by an overarching intelligence. This hypervisor or management software now takes over the central control of all components of the infrastructure appliance, which consists at least of network, storage and server.

Hyperconvergence means software-defined

The principle is similar to a cloud service: the hardware is not visible to users and administrators, they access the distributed resources via an abstracted layer with virtual servers. HCI systems are thus intended to combine the performance and reliability of an in-house data center with the economy and scalability of a cloud.

At the same time, they are often the prerequisite for demanding hybrid scenarios with access to a distributed pool of resources in both the in-house private and public cloud. In some cases, the management software is even capable of managing software such as databases, Kubernetes, key-value stores and other IT services important to developers.

HCI systems have advantages and disadvantages - whether or not they are the best solution in a specific application varies depending on the framework conditions. The main goal is to simplify the IT infrastructure and accelerate deployment processes: For example, there is no need to set up the individual devices individually and the separate, often proprietary operating systems must be coordinated. Comparatively inexpensive standard products can be used as hardware, which further increases the cost efficiency of HCI solutions during operation.

The benefits of hyperconvergence

While in conventional data centers external storage systems are usually connected, HCI appliances use so-called Direct Attached Storage (DAS), i.e. hard disks that are directly connected to the server. The central software layer manages the storage capacities (software-defined storage) and distributes them according to the needs of the applications. This allows a more flexible use of limited resources.

The connecting component is a software-based network (SDN), whose functions do not depend on dedicated hardware, but can be dynamically assigned to free devices. While conventional networks require configuration changes to be performed in parallel on several devices, the SDN separates the control from the hardware. This makes the hardware easier to exchange and cheaper, and IT infrastructure solutions can be flexibly adapted to changing requirements.

The benefits of hyperconvergence

While in conventional data centers external storage systems are usually connected, HCI appliances use so-called Direct Attached Storage (DAS), i.e. hard disks that are directly connected to the server. The central software layer manages the storage capacities (software-defined storage) and distributes them according to the needs of the applications. This allows a more flexible use of limited resources.

The connecting component is a software-based network (SDN), whose functions do not depend on dedicated hardware, but can be dynamically assigned to free devices. While conventional networks require configuration changes to be performed in parallel on several devices, the SDN separates the control from the hardware. This makes the hardware easier to exchange and cheaper, and IT infrastructure solutions can be flexibly adapted to changing requirements.

Not only advantages

While the hardware situation is simplified, the complexity of the software increases. The virtualization software (hypervisor) is multi-layered and multifunctional and thus more complex than the individual operating systems of the devices.

The hypervisor and sophisticated security systems become the central element of the entire infrastructure, making the decision for or against a particular product or vendor critical to success. The operation of a distributed storage solution is also often more complex than that of a traditional storage array. In addition, switching to a new IT infrastructure paradigm always involves effort, investment costs and risks.

When is it worth thinking about HCI?

For companies that want to switch from a hardware-centric to a virtualized environment, the hyper-convergent approach is a good option. Especially for virtual desktop infrastructures (VDI), HCI systems are the appropriate basis. This is due to the fact that constant changes caused by applications in the desktop environment can be responded to quickly. At the same time, a maximum of security is guaranteed by central control.

The high performance and agility also make HCI interesting for performance-intensive scenarios such as agile software development (DevOps), applications in the Internet of Things (IoT) environment or Big Data, since a modern HCI solution supports the "infrastructure-as-code" paradigm.

IT experts thus automate comparatively complicated operating and work processes with the help of modern API interfaces, thus leading to a significant reduction in IT operations costs. If a company needs a rapidly deployable data center for a foreseeable workload, it can purchase a completely finished HCI box as a software appliance or - even more flexibly - rent it as Infrastructure-as-a-Service (IaaS).

The danger of oversizing

Nevertheless, companies should not make hasty decisions. Such preconfigured offers do not always cover all individual needs. A change from individual established systems to a new hyper-convergent infrastructure can be even more challenging.

In most cases, not all functions and systems of the previous infrastructure can be mapped. It is important to carefully weigh up how much simplification is possible and sensible. Dependencies on individual providers (the dreaded vendor lock-in) should be avoided wherever possible.

Whether an HCI environment is the appropriate infrastructure depends on the specific application. For this purpose, it is necessary to first deal in detail with the goals of hardware procurement and the actual requirements. In other words: HCI is less suitable as a supplement if the existing IT reaches resource limits.

HCI systems are themselves easily scalable, but usually by means of relatively high, step-by-step expansion steps. This means: In case of expansion, a complete HCI box is added, even if only little additional storage is required. Due to the comparatively high acquisition costs for HCI systems, customers experience high jump-fixed costs.

The original article in german can be found here.

 

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