Linux Servers

A computer consists of one or more processors, memory, and I/O devices. I/O devices are connected to the computer through I/O buses such as PCI. Additionally, some computers have service processors to assist in system control (booting, error handling) and monitoring (power, cooling).

A server is a computer that provides services to other computers. For example, a DNS server is a computer that provides the domain name lookup service to other computers connected to it via a network. A computer functioning as a server is not limited to providing only one service, although for simplicity and security reasons, it is common to restrict a server to a single service.

One of the most appealing features of the Linux kernel is its modular design. This design has made it relatively easy to port the Linux kernel to new architectures or enhance and extend existing architecture ports to support new features. It is also one of the fundamental reasons why Linux has become so popular. Today, Linux runs in computing environments that range from embedded systems to desktops to entry-level and enterprise-level servers to proprietary mainframe systems. Linux has probably made its biggest impact in the small- to mid-range server market. Linux runs well on servers with two to four CPUs, although current stable kernels support up to 32 CPUs. Two to four CPU servers are currently considered the Linux "sweet spot" from a performance point of view.

In the following section, you will learn about systems and processors. We will discuss how a computer is configured to run as a server, as well as mixing processors within the same system.