Cloud services have given IT an expanded portfolio of options to deliver desktops and applications to users. Still, Desktop as a Service (DaaS) may not be ready for primetime
Cloud-based desktops allow for greater elasticity, address the challenges of mobility and help to fulfill the business requirements for disaster recovery. Implementing DaaS may even reduce the burden on internal IT. However, we have to consider: Are cloud services ready for general users or are they still a point solution for specific needs?
To determine if either on-premise desktop virtualization or Desktop as a Service is right for you, let's review the differences between local and cloud-hosted virtual desktops.
Benefits of DaaS
The greatest benefit of DaaS is the ability to scale up and down the compute resources to meet changing demands. DaaS service providers are scaled for multi-tenancy, so the available compute resources can be used and returned to the pool with little or no penalty. Some providers may only require a reboot or a newly provisioned virtual desktop. Both methods are noninvasive to the end user. With proper management of user settings and content (profiles, personal documents), even moving the user to the newly provisioned VM could be seamless.
Cloud-hosted virtual desktops also offer higher availability guarantees than on-premise VDI. DaaS service providers such as Rackspace, Desktone and TuCloud, and smaller ones such as InfinitelyVirtual, use Tier 1 data centers. That means customers get the benefits of redundancy, high availability, optimized power and sometimes even features such as replication to other locations for data protection.
As with any IT service or product, DaaS brings its own challenges. Here's how to overcome them and mitigate the risks.
Network quality. Neither on-premise nor cloud-hosted virtual desktops are rid of one of the major hurdles of VDI: the impact of poor network quality. The network actually affects cloud-hosted desktops more negatively because the protocol delivery is done over the public Internet. On-premise systems usually have the benefit of internal LAN quality and/or QoS-controlled WANs. That means VDI traffic is appropriately prioritized and latency is either prevented or overcome.
More on cloud-hosted desktops
Deciding between cloud-based desktops and VDI
Weighing VDI vs. cloud-hosted desktops
To solve this problem, establish a private connection between your corporate network and your DaaS provider. Companies such as Rackspace allow you to include the hosted virtual desktop system in your corporate network by having your WAN provider deliver a connection to its facility. If you do not have a corporate network, ask your DaaS provider whom they prefer. You can then replace or supplement your office's Internet connection with the same provider -- reducing the number of hops and hand-offs from your ISP to your DaaS provider's network.
Visibility and control. Most DaaS providers only give you control of hosted virtual desktop provisioning and administration of each VM's operating system. Access to the hypervisor and underlying hardware is usually prohibited. This gets IT out of the infrastructure and support arena, but the lack of visibility and control does bring some challenges.
One of those obstacles is the lack of insight into performance bottlenecks that could cause a poor user experience. For example, if the DaaS provider's shared storage area network (SAN) has oversubscribed IOPS, it will result in slow file read-and-write times for users. The provider should monitor resource usage to scale the infrastructure and limit or even prevent overutilization.
You can also implement a client-based performance monitoring tool to record and report the user experience.
Another way to mitigate slow hosted virtual desktop performance is to overallocate resources to power users' VMs. Most DaaS providers allow you to purchase and reserve compute resources. For example, instead of purchasing a 2-core, 4 GB VM for that Finance department user that runs complex macros once a month, get him or her a 4-core, 8 GB or 16 GB VM.
Hosted virtual desktop licensing. Contrary to popular belief, Desktop as a Service does not take care of your virtual desktop licensing headaches. Microsoft has empowered Infrastructure as a Service and DaaS providers with pay-as-you-go licensing that they can then bundle into their services, but the Service Provider License Agreement does not yet provide rights for Windows workstation licenses. Therefore, you must purchase a valid license if using a thin client to access the hosted virtual desktop, or put your local system on a valid Software Assurance license to gain the benefits of Virtual Desktop Access.
Other major software vendors have yet to provide similar licensing programs to DaaS providers. So, don't change your budgeting practice for users' software costs. If you are estimating a total cost of $2,000 per user every three years, keep that in your budget because it will likely not be reduced by moving from on-premise VDI to DaaS.
DaaS offers significant benefits over on-premise VDI, but it does have some risks. Try it out! Most DaaS providers allow you to start a free trial. A simple sign-up process provisions you a hosted virtual desktop that you can use in a matter of minutes.
This was first published in November 2012