Mark Berry December 12, 2009
A non-profit customer has an underutilized server and a desktop due and budgeted for replacement. Would it make sense to replace the desktop with a thin client, and run the needed programs in a virtual instance on the server?
I blogged earlier about Microsoft Desktop Virtualization Licensing for the SMB. Mostly for licensing reasons, it doesn’t make sense to do full virtual desktops. So that leaves the option of running a terminal server to host the customer’s apps.
This is actually an attractive option for this customer. Several users, some of whom are volunteers, log in to desktops from home. Since desktop login is limited to one person at a time, they have to work when no one is at the physical desktop and no one else is logged in remotely. Giving them access to a terminal server instead would eliminate those conflicts. But that is a “nice to have,” not something that would drive this project.
Comparing the Projects
Let’s look first at what would be required to replace this desktop. I making several assumptions here: desktops are fairly powerful Optiplex 960s from Dell Outlet; customer has Microsoft Open licenses with Software Assurance on existing server and desktops; and the customer qualifies for Microsoft non-profit pricing. What’s involved in replacing one desktop? What if it were three desktops?
|Replace Desktop with Desktop||Replace Desktop with Thin Client|
|Tasks||- Buy desktop ($670)
- Clean install of OS (move existing Software Assurance to new desktop)
- Join to domain
- Install apps
|- Virtualize existing server under Hyper-V Server 2008 R2 (free)
- Buy 2nd Windows Server Standard Open license with Software Assurance ($172 non-profit price)
- Buy 7 RDS CALs ($224 non-profit price)
- Install Windows Server 2008 R2 Standard server as a 2nd virtual machine and join to domain. Activate Remote Desktop Services role. Install all apps requiring remote access.
- Buy either an entry-level or high-end thin client ($199 or $479)
- Set up thin client on network.
|Materials Cost replacing 1 desktop||$670||$595 with $199 thin client
$875 with $479 thin client
|Materials Cost replacing 3 desktops||$2010||$993 with $199 thin clients
$1833 with $479 thin clients
Obviously the costs in the right column would be substantially higher if the customer did not qualify for non-profit pricing. But it was the fact that they do qualify that made me think we might justify this project when just replacing one desktop at first.
Audio, Video, RDP, and Choosing a Thin Client
Hewlett-Packard has a new thin client, the t5325, currently available at an introductory price of $199. Sporting a 1.2GHz processor, 512MB of SDRAM, and DVI-I with a VGA converter, it’s a pretty nice little unit. And at that price, we might justify the thin client route when replacing only one desktop. So I bought a t5325 to see what I could get for $199.
Quite a lot, actually
There are definitely some quirks in the t5325 (probably due in part to it being a brand new product) but overall the setup is quite flexible and easy, and running standard Windows apps over RDP works amazingly well.
However, if a thin client is to replace a desktop, at least in this environment, it needs to be able to handle basic audio and video as one might encounter when browsing the web or playing an AVI or WMV video clip. This, unfortunately, is where the t5325 falls short.
Multimedia Redirection Matters
After playing with the t5325, and after reading this excellent post on the Remote Desktop Team Blog, I finally “got it”: you might as well forget about audio and video via RDP if you’re not redirecting multimedia to the client.
What is multimedia redirection? It’s passing the media stream directly to the client in its compressed form, allowing the client to format and play it. Without multimedia redirection, content must be rendered on the server and then passed as bitmaps to the client. Depending on the the power of the client and server, that may work more or less well, but it chews up CPU power on the server.
To test this, I tried playing back an AVI video while connected via Remote Desktop from three different clients: the HP t5325 running RDP 5.2, a Windows XP SP3 machine still running RDP 6.1, and Windows 7 running RDP 7. Here are my testing notes:
HP t5325 and RDP 5.2: Video jerky; sound awful (unintelligible, scratchy). At one point I had somehow disabled sound and the video was okay. Server CPU 43% – 54% during playback. (I should note that I also tested connecting the t5325 via RDP to a Windows XP desktop and playing back a YouTube video. In that test, audio and video were acceptable, so the t5325 may be having issues with the way Windows Servers 2008 R2 serves audio and video.)
Windows XP SP3 and RDP 6.1: At first, audio and video were decent but badly out of sync with each other. I set up Medium quality audio redirection as described in this blog post. After that, audio and video are okay; sync is much better but still not 100%. Server CPU utilization is 75% – 100% during playback.
Window 7 and RDP 7: Audio and video are smooth and in sync. Server CPU utilization during playback is 4% – 12% because audio and video are being streamed, not rendered on server.
The difference with Windows 7/RDP 7 was so dramatic that I was “sold” on multimedia redirection.
Multimedia Redirection in a Thin Client
HP, Wyse, and no doubt other thin client vendors offer various kinds of add-on software to enhance audio-video playback. I did not research that in depth, but I did note that HP’s offering, Remote Graphics Software, is only available on thin clients running XP Embedded (XPe) or its replacement, Windows Embedded Standard (WES). (Click Buy Online to see pricing from $50 to a site license at $154,000!)
For completing my simple chart above, I decided to look for a thin client that supports RDP 7, with the assumption that I would get the desired multimedia redirection. No doubt RDP 7 will become a common feature of WES-based thin clients, but it looks like 10ZiG is one of the first to offer it. Their blog article describes some of the benefits. Reviewing their list of thin clients aimed at virtual desktops, the RBT-416v is the lowest-numbered model to support RDP 7. System ID Warehouse offers that model for $479, so that’s the figure I used in my comparison above. HP’s thin clients running WES (though not yet listing RDP 7) are comparable in price ($429 – $550).
Entry-level thin clients like the HP t5325 offer an attractive price point and may be ideal for some applications (kiosks or data entry terminals, for example). But to get the “desktop experience” when playing audio and video, yet without overly taxing the server, you’ll need a higher-end thin client that supports multimedia redirection.
The cost of higher-end thin clients is on par with basic desktops. In a very small environment, that makes it difficult to justify the time and cost involved in setting up a terminal services infrastructure to handle the RDP sessions. However as the number of desktops to be replaced increases, the economies of scale (not to mention power savings, management simplicity, and longevity) make thin clients look increasingly attractive as desktop replacements.