Among VPS hosting technologies, OS level virtualization is a front runner. It enables an OS’s kernel to devote resources to more than one user space, giving each the appearance that it is a standalone server. So a user gets the impression he or she is using an independent server, while the server is itself isolating each user to give that impression. In general, the server in turn can devote or detract from the resources given to each user according to their need. Conversely, if too many resources are required by one user, functionality allows limits to be imposed so that the operability of other users is not affected.

Note that the negative aspects of these management features may not be required by a hosting service if it itself has the resources to deal with the extra capacity.

What are the benefits and disadvantages to use of this technology?

An OS can operate in a capacity that could be described as virtualization in one of two ways: It can share its file system among the partitions, or it doesn’t.

Partition that replicates a whole system – known as a whole system virtualizer – requires greater overhead as they take up an entire file system in their own right. Technically speaking, and as a general rule, operating system level virtualization cannot allow “guest” operating systems – there is no compatibility between Linux and Windows, for example. However, these limitations may fall away as technology improves or the need increases.

When sharing the file system, the issue of file systems is overcome although interoperability between guest OSs and hosts is still a problem.

But when used with a degree of common sense, the technology saves space and makes things easier to back up. The boons to this technology mean that a hosting service has limited overhead and is more efficient because programs in the server – regardless of which partition they’re in – can use the one system call interface.