"The landscape of the cmarket in 2009 will be substantially different and more competitive as the industry focus shifts to management and automation. A number of virtualization management startup companies, many of whom are VMware partners, are looking to capitalize on this trend, each bringing its own unique value proposition to the table and hoping to advance the state of the art", says Tom Valovic in an article about virtualization published in the website Virtualization Review.

Mr. Valovic point readers attention to a company called Netuitive. He explains that Netuitive has been in the BSM and performance management business for almost 6 years and has over 200 enterprise class customers such as Cigna, Verizon, NTT, the US Army and MetLife.

The author says that the company's main advantage is a patented algorithm that its performance management software uses to provide continuously adaptive, self-learning capability.

Tom Valovic explains how Netuitive entered the virtualization market. The company released virtualization product "Netuitive SI" for VMware in March 2007. It helps VPS consumers to extract information about the behavior of each virtual machine (VM) and host running in a VMware ESX environment. Read the story in Virtualization Review.

Xen is an unique technology, a powerful Open Source industry standard for virtualization that it a set for virtualization of x86, x86_64, IA-32, IA64, PowerPC, and other CPU architectures.

The Xen's main advantage is that it allows a several guest OS to be executed on the same physical server. It makes possible each of these OS to operate in conjunction with others on the server.

Xen system is structured with the Xen hypervisor (Virtual machine monitor) as the lowest and most privileged layer. Above this layer can work guest several OS, which the hypervisor schedules across the physical CPUs. In this software infrastructure the first OS is "domain 0" (dom0). It is booted automatically when the hypervisor boots and given special management privileges and direct access to the physical server. To start any of the other OS ("domain U" (domU)), the Xen's administrator has to log into dom0.

Those who want to use have to insert Xen's software layer between the host server's hardware and the OS. This creates an abstraction layer that allows each physical server to run one or more virtual servers effectively decoupling the OS and its applications from the underlying physical server.

Xen allows modified versions of Linux, NetBSD and Solaris to be used as the dom0. Other modified Unix-like OS can installed and executed as OS operating systems (domU). In Xen 3.0, unmodified versions of Windows can also be used as guest OS if the CPU supports x86 virtualization.

Why Xen?

Hypervisors like Xen are used by web hosting companies to provide Virtual Dedicated Servers. In general, the server virtualization allows web hosts to consolidate resources, to increase utilization, and ability to respond dynamically to any faults by re-booting virtual server or even to move it to a different hardware. In virtual environment it is also possible to securely separate virtual OS, and to support legacy software as well as new OS instances on the same server.

Xen supports live migration of a virtual server from one physical machine to another. It also allows workload balancing and avoids downtime.

Xen can be used on a PC or server that run Linux and at the same time have Windows installed. Although such systems are used in a dual boot setup, Xen makes possible to start Windows "in a window" from within Linux, and to run applications from both systems at the same time.

According to Xen's website "Xen’s paravirtualization technology is the fastest and most secure virtualization software in the industry. The producers of Xen also say that it offers "near-native performance for virtual servers with up to 10 times less overhead than proprietary offerings, and benchmarked overhead of well under 5% in most cases compared to 35% or higher overhead rates for other virtualization technologies".