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I could read == Short comparison ==The three techniques differ in complexity of implementation, breadth of OS support, performance in comparison with standalone server, and level of access to common resources. For example, VMs have wider scope of usage, but poorer performance. Para-VMs have better performance, but can support fewer OSs because one has to modify the original OS. Virtualization on the OS level provides the best performance and scalability compared to other approaches. Performance difference of such systems can be as low as 1…3%, comparing with that of a book about this without fniidng standalone server. [[Virtual Environment]]s are usually also much simpler to administer as all of them can be accessed and administered from the host system. Generally, such real-world approaches!systems are the best choice for server consolidation of same OS workloads.
Most applications running on a server can easily share a machine with others, if they could be isolated and secured. Further, in most situations, different operating systems are not required on the same server, merely multiple instances of a single ''operating system''. OS-level virtualization systems have been designed to provide the required isolation and security to run multiple applications or copies of the same OS (but different distributions of the OS) on the same server. [http://openvz.org/ OpenVZ], [http://www.swsoft.com/products/virtuozzo Virtuozzo], [http://linux-vserver.org/ Linux-VServer], [http://www.sun.com/bigadmin/content/zones/ Solaris Zones] and [http://www.freebsd.org/doc/en_US.ISO8859-1/books/arch-handbook/jail.html FreeBSD Jails] are examples of OS-level virtualization.
== Where to go further ==
