Exclusive: Virtual enlightenment through Xen

Xen has had a relatively rough road since it began as a research project at the University of Cambridge. Early releases of the open source virtualization package were quite buggy, yet highly touted by major players in the Linux field, which has led many to view the project skeptically.

Initial packaging of Xen into Fedora Core 4 and 5 releases didn’t help matters when it became clear that it was at best difficult to run and at worst simply broken right out of the box. Later releases have made significant usability and functional improvements, and the next release will officially include support for Windows guests, but it still lacks the comprehensive management framework offered by VMware. Make no mistake: Xen works, but it’s is still in its infancy as an enterprise virtualization solution.

Demonstrating Xen’s enterprise potential is Virtual Iron 3.1, which, as do XenEnterprise and Enomalism, seeks to leverage the open-source model to provide a viable alternative to VMware at a significant cost savings.

Before turning to Xen, Virtual Iron had spent two years developing a homegrown hypervisor technology aimed not at consolidating many virtual servers onto a single physical server, but allowing a single virtual server to run across multiple physical servers. Although this was certainly a worthwhile concept, the pace of processor development and the progress of clustering technologies were beginning to render this concept outdated before it even matured.

Pumping Virtual Iron
The upcoming release of Virtual Iron 3.1 lacks many of the advanced features of VMware’s Virtual Infrastructure Server 3, but it does showcase that VMware’s competition is not terribly far behind. In some ways, in fact, the competition is actually ahead: Virtual Iron 3.1 supports as many as 16 CPUs and 96 GB of RAM per virtual machine, compared with VMware’s current limits of four CPUs and 8 GB of RAM.

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Moreover, Virtual Iron extends Xen by enhancing memory management to allow 32-bit and 64-bit guests to run side-by-side, full virtualization to allow guest OSes to run completely unmodified (the current Xen release requires the guest OSes to be modified to run in a Xen environment), and significant work to increase I/O performance of guest OSes. These features will be present in the forthcoming Xen 3.1 release, but Virtual Iron is offering them now, with the GUI management tools.

Virtual Iron 3.1 is a pure Java application that can find a home on a Windows or Linux server, and it ships as a binary GUI install wizard. The setup is minimal, and this first-built server is the equivalent to VMware’s VirtualCenter with one important difference: It serves as the host server deployment system as well as providing the management tools.

When installing Virtual Iron 3.1, it’s recommended to build the server with several network interfaces. One of these NICs will become a management network that should be constructed as an isolated network segment between all virtualization host servers and the management server. This is because by default the Virtual Iron 3.1 server will act as a DHCP/PXE boot server, making deployment of virtualization hosts generally as easy as turning on a new server on that segment.