“BSD users can improve system security with that operating
system’s jail mechanism, which creates a partition of resources,
thereby creating a logical barrier between services running inside
different such jails. Under Linux, an application called
Linux-VServer implements pretty much the same functionality. It
partitions a system’s resources–namely CPU, memory, hard disk, and
network–so that processes inside of the partitions are limited to
their context, which makes denial of service attacks less likely to
succeed. This is one reason why many hosting companies use virtual
servers.“Linux-VServer allows you to create virtual private servers and
security contexts, which operate like normal Linux servers but
allow many independent servers to be run simultaneously in one box
at full speed…”