What is a Server ?

A computer program or apparatus that offers a service to another computer program and its user, also known as the client, is referred to as a server. The actual computer that a server program runs on in a data center is also frequently referred to as a server. It's possible the device serves as a dedicated server or serves other functions.

A server program responds to requests from client programs, which may be operating on the same computer or on different machines, in the client/server programming model. Depending on the application, a computer may act as both a client and a server to other programs requesting services from it.

How servers work

A real equipment, a virtual computer, or software that provides server services can all be referred to as servers. Depending on how the word "server" is employed, there are many different ways that a server might operate.

Virtual and physical servers

A computer used to run server software is all that a physical server is. In the following section, the distinctions between a server and a desktop computer will be thoroughly covered.

A virtual server is a representation of a physical server in the virtual world. A virtual server has its own operating system and applications, just like a real server does. These virtual servers are kept apart from any others that may be running on the actual server.

Installing a hypervisor, a lightweight software component, on a physical server is the first step in establishing virtual machines. To make the physical server capable of acting as a virtualization host is the hypervisor's responsibility. The virtualization host makes one or more virtual machines accessible to the actual server's hardware resources, including CPU time, memory, storage, and network bandwidth.

Administrators can assign particular hardware resources to each virtual server through an administrative console. Because numerous virtual servers can run on a single physical server rather than each workload requiring a separate physical server, this significantly reduces the cost of hardware.

Server software

An operating system and an application are the two software parts that a server must have at the very least. The server application is run on a platform provided by the operating system. It offers the application's dependency services and access to the hardware resources on which it depends.

Additionally, the operating system gives clients a way to communicate with the server program. For instance, the operating system determines the IP address and fully qualified domain name for the server.

Desktop computers vs. servers

Desktop computers and servers have some similarities and some differences. The majority of servers run the same software as X86/X64 desktop computers and are based on X86/X64 CPUs. Physical servers frequently come equipped with numerous CPU sockets and error-correcting memory, in contrast to the majority of desktop PCs. Additionally, servers typically accommodate much more RAM than the majority of desktop computers.

As mission-critical workloads are frequently run on server hardware, server hardware manufacturers design servers to support redundant components. It's possible for a server to have redundant network connections and power supply. A server can keep running even if a crucial component fails thanks to these redundant components.

In terms of form factor, server hardware differs from desktop hardware. Modern desktop computers frequently come in the form of tiny towers that can fit under a desk. Even while few companies still sell tower servers, the majority of servers are made to be rack mounted. Depending on how much rack space they take up, these rack mount systems are referred to as having a 1U, 2U, or 4U form factor. For example, a 2U server uses twice as much rack space as a 1U server.

The operating system is yet another important distinction between a desktop computer and a server. Although a desktop operating system may be able to carry out some server-like tasks, it is neither designed nor authorized to replace a server operating system. An example of a desktop operating system is Windows 10.

Microsoft's virtual machine platform, Hyper-V, is a part of some editions of Windows 10. While Hyper-V is compatible with both Windows 10 and Windows Server, Windows 10's hypervisor is primarily intended for usage in development environments while the Hyper-V version bundled with Windows Server is created for operating production virtual servers.

There are licensing considerations to make even though a company might theoretically deploy a virtual server on top of Windows 10 Hyper-V. Resiliency features are also included in Windows Server Hyper-V that are absent from the Windows 10 version. For instance, failover clustering and virtual machine replication are supported by Windows Server.

A local network of devices can also access files using the Windows 10 operating system. But massive file sharing was never intended for Windows 10. However, Windows Server can be set up to function as a fully functional file server. To give superior performance, scalability, and resilience than what one physical server could provide alone, a distributed file system can be set up across an entire server farm in large businesses.

Types of Server

Servers are frequently grouped according to their function. Here are a few illustrations of the various server types that are accessible:

Web Server: A computer application called a web server delivers requested HTML files or pages. In this scenario, the client is a web browser.

Application Server: The business logic for an application software is provided by an application server, a program running on a computer connected to a distributed network.

Proxy Server: An endpoint device, such as a computer, and another server from which a user or client is requesting a service are connected using software known as a proxy server.

Mail Server: A mail server is a program that passes outgoing emails for delivery and receives incoming emails from local users (users on the same domain) and remote senders.

Virtual Server: A virtual server is a program running on a shared server that is set up to give each user the impression that they have total control over the server.

Blade Server: a server chassis that houses numerous thin, modular electrical circuit boards, also referred to as server blades. Each blade is a separate server that is frequently devoted to a single application.

File Server: A computer called a "file server" is in charge of centrally managing and storing data files so that other computers connected to the same network can access them.

Policy Server: A policy server is a security feature of a policy-based network that supports file tracking and control and authorisation services. 

Database Server: Server hosting databases: This server is in charge of hosting one or more databases. Database queries are executed by client programs to read data from or publish data to the server-hosted database.

Print Server: One or more network-attached printers are made accessible to users using a print server, also known as a print device by some server suppliers. The print jobs that users submit are placed in a queue on the print server. Depending on the job type or the person who submitted the print job, certain print servers have the ability to prioritize the jobs in the print queue.

Server components

Hardware

There are numerous components and subcomponents that make up servers. A rack mount chassis with a power supply, a system board, one or more CPUs, memory, storage, a network interface, and a power supply normally makes up the hardware of a server.

The majority of server hardware has a dedicated network port that facilitates out-of-band management. Independent of the operating system, low-level server management and monitoring are possible with out-of-band management. Systems for out-of-band management can be used to remotely turn on or off the server, set up an operating system, and check its health.

Operating System

The operating system for the server is another element. The platform that makes it possible for programs to execute is a server operating system like Windows Server or Linux. The operating system facilitates network connectivity and gives applications access to the hardware resources they require.

The server's ability to function is made possible by the application. A database application, for instance, would be run by a database server. Similar to a web server, an email server has to execute a mail program.

Choosing the right server 

When choosing a server, there are several things to take into account, such as virtual machine and container consolidation. Based on the use cases, determine which features are crucial when selecting a server.

A number of protection, detection, and recovery elements should be taken into account when thinking about security capabilities, such as native data encryption to safeguard data both in transit and at rest, as well as persistent event logging to keep a permanent record of all activities. 

The selection of disk types and capacity is crucial if the server will use internal storage because it can significantly affect input/output (I/O) and resilience. 

As virtualization makes it possible for fewer servers to support more workloads, many enterprises are reducing the number of physical servers in their data centers. The amount of servers that a company needs to host on-site has also altered as a result of the rise of cloud computing. 

More functionality squeezed into fewer boxes can save overall capital costs, data center floor space requirements, and power and cooling requirements. However, hosting more workloads on fewer boxes can also increase business risk since more workloads will be impacted if the server fails or must be taken offline for normal maintenance.

Both the system's important configuration and physical components should be covered in a server maintenance checklist.