Xen masters take aim at VMware
Virtual Iron and XenSource offerings lack power and polish of the virtualization leader, but they're gaining fastFollow @pvenezia
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Virtual Iron is also relatively picky about hardware support. If you're not running the newer Intel-VT or AMD-V CPUs in your server, you're out of luck. This restriction will have an impact on smaller infrastructures hoping to leverage slightly older hardware in a virtualization design. On the other hand, by requiring the newer virtualization extensions at the CPU level, Virtual Iron can leverage those performance enhancements to provide a better overall experience.
In the lab, I tested Virtual Iron 3.7.1 by installing the management server on an older Dell PowerEdge 2800 with two 3GHz Intel EM64T CPUs, 4GB of RAM, and a four-spindle RAID 5 array running CentOS 4.4. These specs are far above the minimum requirements for the management server; all you really need is a single CPU with 1GB of RAM and 30GB of available disk. The Java-based installer required very little interaction other than a license file, and the server was ready to go.
The administration console for Virtual Iron, dubbed the Virtualization Manager, is Java-based and accessed via browser. I ran the app on Windows, Linux, and Mac OS X without hassle, which is a definite leg up over VMware's Windows-centric management tools.
Virtualization Manager is relatively well laid out, and navigation and configuration are simple. The basis of the application is that every action or set of actions must be accompanied by clicking Commit. This is both a blessing and a curse. It's easy to step through several configuration options and wonder why nothing is happening, until you remember that the actions have yet to be committed. On the plus side, it's harder to make inadvertent configuration errors because changes don't happen immediately.
I built several Linux and Windows VMs, both 32- and 64-bit, and found the experience straightforward and easy. I had problems booting from ISO images in many cases, though direct CD and PXE installations were no problem. Both Windows and Linux guests are supported with full hardware virtualization, unlike Xen's paravirtualized Linux guests, and the OS support is also broader than Xen's. On the other hand, the VS Tools drivers that can be installed in the guest OS only support certain distributions, and even then, only specific kernels on specific distributions. Thus, kernel upgrades to Linux VMs may result in an inoperable VS Tools installation. VMware overcomes this problem by compiling kernel modules within the guest as needed. Virtual Iron offers new VS Tools packages for specific kernels on its Web site; it also offers the VS Tools source code for customers needing to perform manual compilations, but this process isn't necessarily straightforward.