A virtual private server (VPS) is a
virtual machine
In computing, a virtual machine (VM) is the virtualization/emulation of a computer system. Virtual machines are based on computer architectures and provide functionality of a physical computer. Their implementations may involve specialized hardw ...
sold as a service by an
Internet hosting service
An Internet hosting service is a service that runs servers connected to the Internet, allowing organizations and individuals to serve content or host services connected to the Internet.
A common kind of hosting is web hosting. Most hosting provi ...
. The virtual dedicated server (VDS) also has a similar meaning.
A virtual private server runs its own copy of an
operating system
An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs.
Time-sharing operating systems schedule tasks for efficient use of the system and may also in ...
(OS), and customers may have
superuser
In computing, the superuser is a special user account used for system administration. Depending on the operating system (OS), the actual name of this account might be root, administrator, admin or supervisor. In some cases, the actual name of t ...
-level access to that operating system instance, so they can install almost any software that runs on that OS. For many purposes it is functionally equivalent to a
dedicated physical server and, being software-defined, can be created and configured much more easily. A virtual server costs much less than an equivalent physical server. However, as virtual servers share the underlying physical hardware with other VPSes, performance may be lower, depending on the workload of any other executing virtual machines.
Virtualization
The force driving server virtualization is similar to that which led to the development of
time-sharing
In computing, time-sharing is the sharing of a computing resource among many users at the same time by means of multiprogramming and multi-tasking.DEC Timesharing (1965), by Peter Clark, The DEC Professional, Volume 1, Number 1
Its emergence a ...
and
multiprogramming
In computing, multitasking is the concurrent execution of multiple tasks (also known as processes) over a certain period of time. New tasks can interrupt already started ones before they finish, instead of waiting for them to end. As a result ...
in the past. Although the resources are still shared, as under the time-sharing model, virtualization provides a higher level of security, dependent on the type of virtualization used, as the individual virtual servers are mostly isolated from each other and may run their own full-fledged
operating system
An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs.
Time-sharing operating systems schedule tasks for efficient use of the system and may also in ...
which can be independently rebooted as a virtual instance.
Partitioning a single server to appear as multiple servers has been increasingly common on
microcomputer
A microcomputer is a small, relatively inexpensive computer having a central processing unit (CPU) made out of a microprocessor. The computer also includes memory and input/output (I/O) circuitry together mounted on a printed circuit board (PC ...
s since the launch of
VMware ESX Server
VMware ESXi (formerly ESX) is an enterprise-class, type-1 hypervisor developed by VMware for deploying and serving virtual computers. As a type-1 hypervisor, ESXi is not a software application that is installed on an operating system (OS); ...
in 2001. The physical server typically runs a
hypervisor
A hypervisor (also known as a virtual machine monitor, VMM, or virtualizer) is a type of computer software, firmware or hardware that creates and runs virtual machines. A computer on which a hypervisor runs one or more virtual machines is calle ...
which is tasked with creating, releasing, and managing the resources of "guest" operating systems, or
virtual machine
In computing, a virtual machine (VM) is the virtualization/emulation of a computer system. Virtual machines are based on computer architectures and provide functionality of a physical computer. Their implementations may involve specialized hardw ...
s. These guest operating systems are allocated a share of resources of the physical server, typically in a manner in which the guest is not aware of any other physical resources save for those allocated to it by the hypervisor. As a VPS runs its own copy of its operating system, customers have
superuser
In computing, the superuser is a special user account used for system administration. Depending on the operating system (OS), the actual name of this account might be root, administrator, admin or supervisor. In some cases, the actual name of t ...
-level access to that operating system instance, and can install almost any software that runs on the OS; however, due to the number of virtualization clients typically running on a single machine, a VPS generally has limited processor time,
RAM
Ram, ram, or RAM may refer to:
Animals
* A male sheep
* Ram cichlid, a freshwater tropical fish
People
* Ram (given name)
* Ram (surname)
* Ram (director) (Ramsubramaniam), an Indian Tamil film director
* RAM (musician) (born 1974), Dutch
* ...
, and disk space.
Motivation
Ultimately, it is used to decrease hardware costs by condensing a failover cluster to a single machine, thus decreasing costs dramatically while providing the same services. Server roles and features are generally designed to operate in isolation. For example,
Windows Server 2019
Windows Server 2019 is the ninth version of the Windows Server operating system by Microsoft, as part of the Windows NT family of operating systems. It is the second version of the Server (computing), server operating system based on the Windows ...
requires a certificate authority
and a domain controller to exist on independent servers with independent instances of Windows Server. This is because additional roles and features adds areas of potential failure as well as adding visible security risks (placing a certificate authority on a domain controller poses the potential for root access to the root certificate). This directly motivates demand for virtual private servers in order to retain conflicting server roles and features on a single hosting machine. Also, the advent of virtual machine encrypted networks decreases pass-through risks that might have otherwise discouraged VPS usage as a legitimate hosting server.
A
dedicated server
A dedicated hosting service, dedicated server, or managed hosting service is a type of Internet hosting in which the client leases an entire server not shared with anyone else. This is more flexible than shared hosting, as organizations have f ...
will meet your requirements, but it will not eat into your budget. The good news is that a VPS can improve the performance of your website. Your site will be safely sectioned off in its own zone, free of traffic from other websites. These elements can make or break your site's ability to give visitors a trustworthy experience. Finally, it is utilized to reduce hardware costs by consolidating a failover cluster into a single server, resulting in considerable cost savings while maintaining the same level of service. The majority of server roles and functionalities are designed to work independently. For example, Windows Server 2019 necessitates the presence of a certificate right and a domain controller on split servers running part of Windows Server instances.
Roles and features on servers are classically planned to work in separation. This is expected to the fact that adding more roles and features increases the number of potential failure points while also increasing the visibility of security threats that placing a certificate authority on a domain controller poses the potential for root access to the root certificate. This drives demand for virtual private servers, which allow conflicting server responsibilities and functionalities to be maintained on a single hosting machine. In addition, the introduction of virtual machine encrypted networks reduces pass-through hazards that may otherwise deter VPS use as a genuine hosting server. Finally, it is used to reduce hardware costs by consolidating a failover cluster into a single server, resulting in significant cost savings while maintaining the same level of service.
Hosting
Many companies offer virtual private server hosting or virtual dedicated server hosting as an extension for
web hosting
A web hosting service is a type of Internet hosting service that hosts websites for clients, i.e. it offers the facilities required for them to create and maintain a site and makes it accessible on the World Wide Web. Companies providing web h ...
services. There are several challenges to consider when licensing proprietary software in multi-tenant virtual environments.
With ''unmanaged'' or ''self-managed'' hosting, the customer is left to administer their own server instance.
''Unmetered'' hosting is generally offered with no limit on the amount of data transferred on a fixed bandwidth line. Usually, unmetered hosting is offered with 10 Mbit/s, 100 Mbit/s, or 1000 Mbit/s (with some as high as 10 Gbit/s). This means that the customer is theoretically able to use ~3 TB on 10 Mbit/s or up to ~300 TB on a 1000 Mbit/s line per month, although in practice the values will be significantly less. In a virtual private server, this will be shared bandwidth and a fair usage policy should be involved. ''Unlimited'' hosting is also commonly marketed but generally ''limited'' by acceptable usage policies and terms of service. Offers of unlimited disk space and bandwidth are always false due to cost, carrier capacities, and technological boundaries.
Many firms provide virtual private server
hosting or dedicated server hosting as an add-on to their web hosting services.
See also
*
Comparison of platform virtualization software
Platform virtualization software, specifically emulators and hypervisors, are software packages that emulate the whole physical computer machine, often providing multiple virtual machines on one physical platform. The table below compares basic i ...
*
Cloud computing
Cloud computing is the on-demand availability of computer system resources, especially data storage ( cloud storage) and computing power, without direct active management by the user. Large clouds often have functions distributed over mul ...
References
{{Reflist
Servers (computing)
Cloud computing