People often ask me for my opinion on which desktop virtualization product is "best." Of course that answer depends on many factors for a given scenario, but one of the most important questions to before deciding is, "How many users are you building this VDI for?" I'm surprised by how often I hear answers like "50" or "100." And when I hear that people are building smaller VDI environments, I can't help but think that they can't do it better, cheaper, or more securely than a cloud desktop / desktop-as-a-service (DaaS) at that scale. So just go to one of the cloud providers and be done!
The reality is that even in 2013, VDI is complex. Sure, there are hardware makers like Nutanix and Simplivity who combine compute and virtual storage into single appliances, and there are virtual storage providers like GreenBytes and Atlantis who let you run advanced virtual storage on the same hardware you use to host your desktops, but that doesn't negate the fact that VDI is some complicated stuff!
If you think about it in terms of effort-to-costs, I've often talked about how you can build some decent VDI now for $500 per user. But that's based around a fair amount of scale. So if you're building a small environment, I'd consider bagging it and just going and buy it from someone who knows what they're doing and can get the huge economies of scale in their environment with savings they can pass on to you.
I mean even if you could build your own VDI for $500 a user, if you can buy VDI for $30 per user per month, you're talking about a 17 month break even point (which is halfway to your hardware refresh anyway), and all that time you wouldn't have to deal with swapping out hard drives, upgrading users, or managing servers.
if you're not following this logic, think about it in the context of other areas of IT. I mean look at Gmail. What is it that makes a private company think they can run an email service more cheaply, more reliably, and more securely than Google? People say, "Yeah, but that means our mail is in the cloud. We need to know where our data is?" Really? Why. For security reasons? What do you think is more secure—Google's servers and datacenters or your office? People say, "But Google doesn't have an SLA!" Um, yeah, that's because they're Google. They don't need an SLA. When Gmail is down it's in the news, and they have about 100x more people than you have all scrambling to fix the problem. (And many of them are the people who wrote the email product!) When your email goes down, you have Ray, your Exchange-certified sysadmin who you've paged several times.)
So when it comes to VDI, I don't know what the exact tipping point is. 50 users? 500? 1,000? Let me tell you, it's big. The company I work for (TechTarget) has about 700 employees. If we decided that VDI was the right solution for the enterprise desktop for our users, there's no way we could do it better than a Desktone or tuCloud. If we went out to a cloud provider, we could spend all of our energy focusing on designing our desktops. We wouldn't have to think about reference architectures or IOPS or LoginVSI metrics or design best practices. We;d just say, "we'll take 700 please" and we'd be on our way. Done.
So regardless of where the exact point it, every company has a number of desktops under which it just doesn't make sense for them to do VDI on their own. And I'll bet if we really dig into it, that number's a lot higher than many of us think.