An in-depth look at converged and hyper-converged technology for VDI

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Innovation lowers converged and hyper-converged infrastructure costs

Thanks to the ever-shrinking cost of all-flash storage and hardware-accelerated graphics, converged and hyper-converged infrastructure are a mainstay in the VDI conversation.

Innovations in converged and hyper-converged infrastructure for VDI have made these technologies more affordable.

New technologies are usually expensive, which limits them to niche areas where the value is high initially. Mainstream adoption only occurs when the cost drops, which makes more general-purpose uses more viable.

That is exactly what happened for converged and hyper-converged infrastructure for VDI as both all-flash configurations and hardware-accelerated graphics have become more affordable. Another significant change is the increase in support for alternative VDI brokers and hypervisors, which reduce the per-user cost of virtual desktop infrastructure.

All-flash storage

The single biggest innovation in VDI in the last few years is all-flash storage. An all-flash array in a converged infrastructure (CI) product or an all-flash hyper-converged infrastructure (HCI) node can deliver consistently great storage performance across all the diverse access patterns inherent in VDI.

The first result of all-flash storage is that users experience high-performance desktops at all times. Second, the bulk of virtual machine (VM) maintenance tasks complete more quickly.

The continuing price drops for flash storage have brought all-flash configurations into reach for more organizations.

Most converged and hyper-converged vendors started with hybrid storage configurations. They used hard drives for capacity and flash storage for performance. As long as the flash was large enough, the desktops ran fast. As soon as the desktops' combined disk working set was larger than the flash, desktop performance suffered. All-flash configurations use flash for the capacity tier in place of slower hard disks. No matter the working set size of the desktops, everything is fast with flash.

The continuing price drops for flash storage have brought all-flash configurations into reach for more organizations. In addition, compression and deduplication can effectively expand flash storage capacity, which further reduces the cost of all-flash HCI and takes away the capacity penalty of full-clone desktops. Deduplicated full clones are as capacity efficient as linked clones or Citrix Provisioning Services streamed desktops.

GPU acceleration

Graphics processing unit (GPU) acceleration for desktops used to be reserved exclusively for workstation-class workloads because GPU cards were so expensive. That meant that GPU acceleration was only present in areas such as oil and gas exploration or computer-aided design (CAD). Now that there are GPU cards that can accelerate VDI for significantly less, hardware GPU is becoming cost-effective for more mainstream power users than ever before.

Hardware-accelerated graphics allow admins to deliver more demanding applications with VDI. This includes CAD viewers and visualization tools. It may simply be that accelerated graphics make for a more responsive general-purpose desktop.

Not every HCI or CI product can have hardware graphics acceleration. GPU cards are usually only available in rack servers. The physical size of an NVIDIA card makes them unsuited to most blades, and "four nodes in 2U" deployments don't have the space for a GPU card.

Alternative VDI vendors

Citrix and VMware take up the bulk of the market, but alternative brokers are showing up more and more.

Hyper-converged tech test

Hyper-converged and converged systems continue to make their way into the data center. Test yourself on the current market, and major differences between the two technologies with this quiz.

When admins evaluate alternative brokers, they must be aware that the brokers do not necessarily have all the features they would find in the more mainstream products. Some are simply a broker and do not have any VM provisioning capabilities. Others require an existing VPN for internet access rather than including their own gateway. Yet most of these brokers also have features -- such as clientless access, session shadowing and Linux support -- that are absent in other VDI products.

VDI vendors that do not have their own hypervisor are supporting less-mainstream hypervisors. For organizations looking to control the cost of their VDI deployments, saving on hypervisor costs can make a big difference. 

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