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Virtualization can make it easier to deliver, manage and secure applications, but deciding on the right approach can be confusing.
Before choosing a method for virtualizing applications, IT administrators must know how they plan to set up their desktop deployments and how their users work.
There are three primary approaches to virtual application delivery: Microsoft Remote Desktop Session Host (RDSH), VDI and desktop as a service (DaaS). Although these technologies are similar in some respects, they're very different in others.
Remote Desktop Session Host
The RDSH service is a role in Microsoft Remote Desktop Services, a set of Windows Server features that support remote access. With RDSH, admins can set up a server to host Windows-based applications or desktops that multiple users access through their client devices. Admins can deploy apps individually or as part of virtual desktops to users across the enterprise. They can then centrally manage and control the apps. The RDSH service takes a session-based approach to delivering desktops or applications. Users connect to the server individually, but the sessions share system resources such as processing and memory.
Because sessions share resources, one session can hurt the performance of another. As a result, RDSH is not well-suited to resource-intensive applications, because they can hog resources. In addition, some applications simply don't run properly on a server operating system or in a multisession situation. Admins also have to manage server deployments differently from desktop deployments, adding to the complexities of updating and patching.
Despite its limitations, RDSH is useful if there's a large number of task workers who use the same applications in similar ways. Organizations might also consider RDSH when they only need to implement a few apps, rather than deliver full virtual desktops.
Virtual desktop infrastructure
VDI hosts desktops inside virtual machines (VMs) in centralized data centers. Unlike with RDSH, administrators can centrally deploy applications to VMs running a true desktop OS.
With VDI, admins have extensive control over their deployments, security and user experiences. This control does come at a price, however. VDI systems can be costly and complex to implement, and they require IT teams to have the resources and expertise necessary to deploy and manage them.
Organizations should consider VDI if their users require a high degree of personalization or require applications that won't run in multisession server deployments. Admins might also look to VDI for delivering applications to a small number of users or if they have applications with specific security or installation requirements.
Desktop as a service
Organizations that don't have the resources to implement VDI should consider DaaS. A cloud-based offering, DaaS delivers virtual desktops and applications without the large initial investments and management resources that VDI requires. Admins do have to sacrifice some control, and the subscription fees that come with premium DaaS offerings can be more expensive over the long term than the costs of implementing VDI.
Service providers take different approaches to DaaS. Some mimic the VDI model, incorporating cloud features such as multi-tenancy, but still delivering a desktop OS. Others take a session-based approach, providing desktops based on a server OS, which helps mitigate some of the licensing issues that come with Windows virtualization.
DaaS limits the degree to which admins can control configurations and security. The service provider decides when and how to implement the infrastructure and protect the data. In addition, DaaS isn't as mature as VDI and doesn't support the same advanced features and functionalities.
Organizations already shipping their workloads to the cloud are good candidates for DaaS, as are those using temporary or contract workers. DaaS might also be a good fit for virtual or distributed offices.
Selecting a technology for virtualizing applications is not an all-or-nothing proposition. Admins can mix-and-match products to best fit the needs of their organizations and users.
A closer look at VDI vs. DaaS
How VDI and RDSH compare
How to set up virtual desktops with RDSH