Will Hyper-V Doom XenServer?

Brian, as I mentioned in a blog entry about his post, believes that Xen (note: not XenServer, which is a paid variant with Xen at its core, but the free, open source Xen hypervisor) could die off, and that the RTM of Microsoft's Hyper-V is the possible death knell.

Simon was the head of XenSource before it was bought by Citrix, and thus has a personal stake in this, as he's put his heart and soul into Xen for years. He thinks Brian is full of hot air in this case.

First, he says that XenServer (Citrix's Xen-based commercial hypervisor), while small, is on a growth curve:

"We have somewhere approaching 4,000 enterprise customers, and about 3000 trained channel partners ... The XenServer market share is small, and growing as rapidly as any such product can given the current VMware brand status, and the fact that we started well behind them."

He adds, correctly, that XenServer is still new in the market, so it makes sense that its share is small.

Simon then goes on to make a very interesting argument: that Microsoft and Citrix are ultimately partners, not competitors, even in the virtualization space. At least on the hypervisor side. Here's the core of his thesis:

"It is important to state yet again that we are not in a competition for server sockets with Microsoft. If that were the case, why would we have helped Microsoft to make Hyper-V a better hypervisor, by developing the shims and drivers that will allow Linux to run with optimal performance on Hyper-V? The founding thesis of XenSource, and the continued strategy at Citrix, is to promote fast, free, compatible and ubiquitous hypervisor based virtualization. If the hypervisor is free, why worry about who delivers it? Let the customer pick the implementation method that they want - the real money is in the up-sell with products that make virtualization valuable for customers."

It sounds like Simon is limiting his "cooperation, not competition" argument to the hypervisor alone, i.e. XenServer vs. Hyper-V. It's the "up-sell" products, as he calls them, where the fight will play out. He specifically mentions XenApp, the former Presentation Server, and XenDesktop, the virtual desktop infrastructure product, as Citrix' two main entries, along with hints of more products to come.

I think, however, that the hypervisor will play a key role in this fight, and shouldn't be overlooked. The reason is that an admin is going to more naturally gravitate to toward the "upsell" products of the hypervisor manufacturer. If you're using ESX, you'll first consider ThinApp (VMware's application virtualization) and VDI, and if they don't offer what you need (unlikely), you're apt to choose those. If you've gone with the Microsoft setup -- Windows Server 2008 and Hyper-V -- you're going to first consider System Center Virtual Machine Manager 2008 as your management console, and App-V (Redmond's app virtualization) as your solutions for those areas (Microsoft's desktop virtualization picture is fuzzier right now, giving VMware and Citrix a decided leg up in that regard). Same with Citrix -- Linux folks who like Xen and have moved to XenServer will give strong consideration to XenApp and XenDesktop.

Simon concedes that Hyper-V is likely to outstrip XenServer in the market, given Microsoft's strategy of using Windows 2008 as the Trojan Horse to slip in Hyper-V. I agree with him on that. But I wonder if that advantage will ultimately result in Citrix taking more aggressive steps to differentiate XenServer from Hyper-V, and less of a buddy-buddy role in the future?

Posted by Keith Ward on 07/02/2008 at 12:48 PM