The Case For VDI In The BYOD Era

The idea of PCs was intensely beguiling when it first appeared. It meant there was a way around long development cycles and rigid IT organizations. It also saved a lot of money.

Thirty years later, this value proposition is getting a lot of scrutiny, and the PC in the enterprise is under intense pressure. The tethered desktop PC has seen pressure from more mobile alternatives for years now, but the general love affair with tablets and phones has caused the desktop/laptop industry to peak and go into steep decline.

There are a couple of alternatives available to an IT department in this mobile era. For some years, enterprises have been locking up laptops so that IT has complete control of configurations and keeps stored images on the network. While aimed at being data-safe, this approach creates restrictions that generate employee resentment and are counter-productive.

The other alternative, virtual desktop infrastructure (VDI) and Desktop-as-a-Service, embrace BYOD and move the desktop onto a shared server. There are quite a few notable players in the market, as the chart shows (courtesy of Citrix/IDC). Consider that a typical client has less than 1% utilization of its resources, since work is generally very episodic. With current technology, 64 or more virtual desktops can reside on one server.

Source: Citrix/IDC

Applications such as document creation and editing now are done on the server, and the output is sent to a browser or app on the mobile device, making it possible to work on a phone or tablet relatively seamlessly. Nothing is permanently stored on the client, making for a very secure working environment.

The client data images are kept on network storage, allowing them to be loaded on demand. This also means that recovery after a failure can be quick, performed simply by restarting on the next available server. The overall result of having virtualized stateless servers is a smaller, more efficient server farm.

[Read how Amazon's new desktop virtualization service could prove a gateway to a post-PC, mobile, and cloud-centric future in "Amazon Workspaces Speeds the PC's Demise."]

The VDI approach has a major drawback, however. While that 1% utilization seems small, being episodic means bursts of intense activity for any one client can occur at any time. That is acceptable most of the time, since the network can perform at least as well as the typically DASD of a dedicated PC. The problem is caused by a “boot storm” that occurs when many desktops are started together.

Hundreds of desktops starting up, at say 9 a.m., mean huge I/O rates until all the images are booted. With traditional HDD NAS boxes, this took forever, and the result is the VDI approach got a black eye. Poor network response time didn’t help.

This problem has been largely resolved in the last three years or so. SSD came along and greatly increased the I/O performance of networked storage. Building on this, flash accelerator cards with cloning and deduplication software boosted things even further. The result is that VDI is becoming an accepted alternative to the desktop PC.

In the last year, all-flash arrays have moved performance even further along. With millions of IOPS, these devices can easily keep up with large arrays of virtual desktops. Networks with 10G Ethernet and even 40G Ethernet connections are common now in these configurations.

As a result, the virtual desktop approach is attaining some notable wins. Britain has taken a leadership role in driving to SaaS solutions generally, and the Cabinet effectively mandated a transition to VDI by pushing most IT efforts to use its G-Cloud app store. In the best IT tradition, the officials are eating their own dog food: Britain’s government is embracing a VDI approach for members of Parliament.

With BYOD a given as a trend, clear solutions for the technology issues and cost-effectiveness, the migration to VDI will continue at a good pace. This will tip the PC market into a steeper decline, but the benefits of a desktop that can be on your phone, tablet or TV are clear. This is the trend of the future, and not just for the enterprise. SMBs will follow the same path.