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Five questions to ask as you compare VDI vs. DaaS

IT pros must know their goals and use cases, as well as the location of their users and data, when deciding between VDI and DaaS. Cost is also an important factor.

Moving to virtual desktops -- either on premises or in the cloud -- is a big decision.

Choosing VDI or desktop as a service (DaaS) can have serious consequences around cost, employee productivity and the desktop user experience. And in some cases, neither is the best option.

Attendees at the Gartner Catalyst Conference learned some tips on evaluating VDI vs. DaaS. Mark Lockwood, research director at Gartner, outlined these five questions that IT pros should ask as they start this process.

What are my goals?

If the main objective is to reduce upfront deployment and management costs, DaaS has the advantage because the cloud provider handles configuration and maintenance in exchange for subscription-based pricing, Lockwood said. DaaS is also the better option if IT needs to support a very elastic workforce. But if the goal is to give users faster access to their desktops and give IT more control, choose VDI, he said.

And don't forget that physical desktops are still an option, if neither VDI nor DaaS will meet these goals.

"If you can't make VDI or DaaS better than physical, you can't afford to pay more to get less for your users," Lockwood said.

What are my use cases?

IT should do extensive use case testing when evaluating VDI vs. DaaS. For offline use cases, physical desktops are the way to go. The only VDI software that allows for offline access is VMware Horizon FLEX, and DaaS isn't a good fit by nature because it requires a network connection to work, Lockwood said.

Also consider that not all DaaS providers have support for graphics-heavy apps, so if that's the use case, cloud is not your best option, he said.

More providers are offering GPU support, but they're not all there yet.
Mark LockwoodResearch director, Gartner

"More providers are offering GPU support, but they're not all there yet," he added.

Daas is best for short-term workers, spinning up a few desktops for a specific reason and supporting new workers during mergers and acquisitions, Lockwood said.

Where are my users?

DaaS providers with multiple data centers allow users to connect to the cloud that's closest to their physical location. That's why DaaS is better than VDI when users are distributed far and wide, Lockwood said.

"If you want to fail spectacularly, treat every user identically regardless of location," he said. "A user in Chicago is going to have great access to the home data center that's in Chicago."

Relx Group, a business information and analytics provider based in New York, uses VDI for its in-house offshore developers. The company has struggled with performance because users are so far from the data center and require access to heavy-duty SQL databases, said Chris Haaker, director of end user compute innovation at Relx.

"It provides a lot of challenges because it's a lot of horsepower for SQL," he said. "VDI wasn't really meant for that."

The Relx office in Miamisburg, Ohio, may deploy Amazon's DaaS offering, WorkSpaces, to improve performance by reducing the distance between users and their virtual desktops, which the cloud provider can host in its data centers around the world, Haaker said.

Where is my data?

Organizations that have all their data on premises will have more success with physical or virtual desktops that are on premises, too, but for those with a lot of data in the cloud, DaaS makes sense, Lockwood said.

"Data is moving to the cloud and will continue to move to the cloud," he said. "If all the data that a specific use case is going to connect to is [in Microsoft] OneDrive … VDI is not the best option. Desktop as a service would be a better choice."

What is the cost?

DaaS and VDI both won't typically save organizations money over physical desktops.

"You implement VDI only because you are getting additional benefits that outweigh the additional cost," Lockwood said. "There are some really edge use cases where VDI or DaaS can save money, but that should never be the primary reason to move."

Rather, the main benefit of DaaS or VDI is to make the desktop user experience better. If an organization picks a DaaS provider or builds an on-premises infrastructure that saves money but productivity doesn't go up, the project is still a failure, Lockwood said.

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