Last week Computer Reseller News published an article by Mario Morejon titled, "Virtualization: The Emerging Desktop." Quoting from the article: "Virtualized desktop technology holds more promise than server-based computing because users are able to experience fully integrated desktop environments. Personalization is relatively easy to set up. This is why Citrix is now in the game. Server-based computing, including Microsoft Terminal Services, is a dying technology."
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My initial reaction was "No. No. Wrong. BS. Nope. No way. Nuh-uh."
Besides, the article was so completely full of inaccuracies and the author obviously has no clue about this space, so I laughed it off and ignored it. But a few days later I realized I was still thinking about it.
And now I ask myself, "Is this possible? Could VDI ultimately replace Terminal Server?"
This blog entry is two parts--both in reaction to Morejon's article. In the first part I'll explore whether VDI could replace Terminal Server. In the second part, I'll point out a few of the big errors in the CRN article. My fear is that people not "in the know" (i.e. our managers) will read it and get all sorts of mixed-up notions about VDI and Terminal Server.
Part 1. Could VDI replace Terminal Server?
For those readers not familiar with my views, let me first state clearly that my bias is towards Terminal Server. Sure, I'm independent and a consultant and always looking out for the best for the people I coach, but let's be honest: I've been working with Terminal Server for ten yers. This "VDI thing" kind of snuck up on me, and at first I didn't really think it had legs at all. But as you might remember from my most controversial article ever, I'm definitely seeing certain scenarios where VDI could be useful. So my "VDI Love" index is increasing.
(Of course "VDI" means a lot of different things, depending on who you ask. For the purposes of this article, I'm using the term "VDI" to mean Windows XP or Vista instances running in a data center, with users connecting to them remotely via a protocol like RDP.)
Could VDI replace Terminal Server-based solutions for SBC? As I see it now, there have traditionally been two major reasons to use TS instead of VDI:
- Given the same hardware, you can typically fit more TS user sessions than VDI Windows XP VMs.
- Since VDI means running a copy of Windows for each user, you have to figure out how to manage all of those Windows instances. With TS you only manage a single OS instance for all the users on a server.
I've written about these two reasons in the past and how I think they're evolving, so it's not really worth re-hashing all of the specifics here. But some quick notes for those who don't want the full dissertation:
First, recent changes in hardware have allowed VDI to "narrow the gap" in terms of number of users per server. Now that most servers are dual and quad core (and moving higher), VMware/Xen/Hyper-V can / might scale up on those boxes as good as (or better even?) than Terminal Server.
Second, if you have some method for managing disk images for your VDI users, the whole "managing all those Windows XP images" isn't too big of a problem. There are lots of ways to manage these disk images: Citrix Provisioning Server (Ardence), disk image snapshotting, etc.
Some people say "well sure, you can manage the images as one if they are stateless, but stateless won't work in our environment." I agree 100%. If stateless doesn't work, then VDI image management will be a nightmare. But the point that I'm making is not comparing VDI to the traditional method. I'm comparing VDI to Terminal Server, and all Terminal Server sessions are (by definition) stateless since all users on the server share the same disk image.
Assuming those two statements are true, the advantages that TS has over VDI are diminished. In that case you could go VDI and get the benefits of Terminal Server and also get the benefit of not having to worry about Terminal Server app compatibility. Plus you could probably hook into something like Citrix Provisioning Server or VMware ACE and "stream" the actual VDI virtual machines to a client device where they could be used offline. You could also move them between servers.
So thinking like that, yeah, I do wonder whether the future of Terminal Server is limited, and whether a single user instance OS (Vista or XP)-based VDI solution might be more practical at some point in the future. (I don't think we're there yet. Maybe in a few years?)
Part 2. That article in CRN was the worst piece of garbage I've ever read
I really don't want to get into a line-by-line rebuttal of this article. And as you just read in Part 1, the ironic thing is that I agree with Morejon's basic idea. But the examples in the article are ignorant, dangerous, and just plain wrong. A few of the major errors:
In the first few sentences, Morejon repeatedly misspelled "Xen" as "Zen." This indicates to me that he doesn't have too much experience in this space, and makes me question his authority for this article.
He goes on: The full desktop experience has never been fully captured within server-based computing. Virtualized desktops do a better job at making users feel that they are in a more normal environment and users have more control over work environments. By contrast, server-based computing provides a highly controlled and locked-down experience. Users only get access to what administrators deem necessary.
This is a classic mistake. He is comparing "virtualized desktops" to "server-based computing." These are not opposites! Virtualized desktops (in the VDI way he describes) is server-based computing! It's just that VDI is server-based computing connecting to a single user OS (Windows XP or Vista), whereas the more traditional Terminal Server-based server-based computing connects back to a multiuser OS (Terminal Server.)
Of course he also talks about "SBC" (i.e. Terminal Server) as being more controlled and locked down, and that users only get what admins deem necessary." I don't think he realizes that TS admins do this on purpose. I really hope that admins also apply this approach to VDI. (But I get the point that with VDI you can be more loose since if a user breaks something, he only impacts himself.)
With virtualization, users do not need to have costly, full-power PC systems on their desks. Since the working experience is coming off a virtual environment, users can have inexpensive thin clients and still have the same experience. Thin client devices even provide more access to remote software installations.
I agree, except he's using this as an advantage of "VDI-based SBC." In reality this is an advantage of all SBC solutions, whether single-user VDI or multi-user Terminal Server, so it doesn't really support his case against TS.
"Companies are finding out that virtual desktops are a logical solution for remote locations," said Tom Cecchini, president of Async Associates, Wixom, Mich. He added that technologies like video streaming, Reader Rabbit (in the educational community) and CAD systems have never been able to work on server-based computing. Thin client is changing the old perception by allowing users to have that power at remote sites."
Again, these problems apply to VDI and Terminal Server-based server-based computing solutions. Video streaming is a *** over SBC, regardless of whether your back-end is a single user OS or Terminal Server.
After trying an original Windows 2003, the installation failed. Engineers tried using virtual floppies on the remote PC manager running the VI client software. However, the virtual floppy drives did not activate and driver files could not be installed. Engineers do not recommend installing OSes into a virtualized environment. It is easier to use an OS image.
Morejon is basically saying "We couldn't figure out how to boot a Windows ISO to install Windows into a VM, so instead we recommend you install Windows onto physical hardware and then do a physical-to-virtual migration." Seriously? This is the team you want to take advice from? The "P2V is the preferred installation method" geniuses at this magazine?
This technology has come a long way since the days of Citrix's ICA
This scares me. Their demo environment used RDP! I feel that this statement is like a "dig" to Citrix, saying that RDP is much better since the "days" of ICA. Which "days" is he talking about? The days of 1998? Because if so, he's right! RDP of 2007 is better than ICA of 1998. (Just like a 2007 Mazda is faster than a 1982 BMW.) Apparently they don't know that ICA is still around.
But that's not the worst part of that statement. If he likes RDP so much better than ICA, fine. But he's using it to prove the point that VDI is better than TS. Except of course you can still use RDP to connect to TS.
Companies should see less traffic on corporate networks when using virtual thin client environments.
Oh man! It's going to take years to undo the damage of this inaccuracy. This statement is straight from the Citrix-angular-flying-briefcase-man of the 1990s. When this dude gets his reader rabbit and video streaming and CAD running via RDP, I can guarantee he's not going to see less traffic on his corporate network!
You get the idea.
The bottom line is I do really think the future of SBC could be more around single-user OS instances. But I sure don't think that because of anything Morejon wrote in that article.
By the way, this article is full of HP and Neoware (now owned by HP) references, including kind of weird references as to what model of HP laptop the engineers used to connect to the management consoles. I sure hope HP didn't pay for this crap!