Virtual private servers are very useful for medium to large websites that have a significant amount of traffic. There is a certain level of complexity from the administration side when it comes to hosting a VPS, however. Dedicated servers are quite easy to manage, as there is only a maximum of one website per server. Shared hosting is also relatively easy to manage, as there are simply a large number of sites thrown on one server.The problem with a virtual private server is the initial setup. VPSs are usually servers with an array of virtual machines running on them. Each virtual machine is a separate operating system running on one primary operating system. This allows the virtual machines to remain separate, but a setup like this can cost a server administrator valuable resources. Every time the virtual machine runs a task or makes a request, the request has to jump from one layer of the system to another (from the virtual machine to the primary operating system, then back). This causes almost every task to use significantly more throughput than it would if it were run on the primary OS.There is a program, however, called Virtuozzo that helps eliminate this problem. Virtuozzo works differently: instead of having multiple virtual operating systems installed on a server, it is set up so that all VPSs run off of the main system. This is done by partitioning the system so that individual VPSs are all on the same operating system, but all act completely independently of each other. Virtuozzo also has a proprietary feature that controls / restricts access to the kernel (primary OS) so that every partition acts completely independently of each other, to the point that no individual partition can cause the entire thing to crash.Despite the fact that all VPSs set up by Virtuozzo are on the same operating system, all VPSs have their own login credentials, core system processes, and network addresses, this allows each of them be rebooted or migrated independently of each other, without taking down the other VPSs. Virtuozzo is a great solution for system administrators that are currently hosting multiple web sites / domains on a single server and it has a reputation for being reliable and secure. It is a very unique product, and has many advantages over running a single server running multiple operating systems. Virtuozzo is definitely worth a second look from any system administrator looking to run his or her server more efficiently.