Editing Virtual private server

{{short description|One of many virtual machines running on a single computer}}
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{{More citations needed|date=December 2024}}{{internet hosting}}

A '''virtual private server''' ('''VPS''') or '''virtual dedicated server''' ('''VDS''')  is a [[virtual machine]] sold [[as a service]] by an [[Internet hosting]] company.<ref name=":0" />

A virtual private server runs its own copy of an [[operating system]] (OS), and customers may have [[superuser]]-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 hosting service|dedicated physical server]] and, being software-defined, can be created and configured more easily. A virtual server costs less than an equivalent physical server. However, as virtual servers share the underlying physical hardware with other VPS, performance may be lower depending on the workload of any other executing virtual machines.<ref name=":0">{{cite web |last=Nguyễn |first=Thành |date=March 2017 |title=Virtual Private Server (VPS) or Virtual Dedicated Server (VDS) |url=https://searchservervirtualization.techtarget.com/definition/virtual-private-server |access-date=13 February 2019 |work=searchservervirtualization.techtarget.com}}</ref>

== Virtualization ==
The force driving server [[Hardware virtualization|virtualization]] is similar to that which led to the development of [[time-sharing]] and [[multiprogramming]] 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]] which can be independently rebooted as a virtual instance.

Partitioning a single server to appear as multiple servers has been increasingly common on [[microcomputer]]s since the release of [[VMware ESX Server]] in 2001.<ref>{{cite journal |last=Waldspurger |first=Carl A. |title=Memory Resource Management in VMware ESX Server |journal=Proceedings of the 5th Symposium on Operating Systems Design and Implementation (OSDI '02) |date=December 2002 |location=Boston, MA |publisher=USENIX Association |pages=181–194 |url=https://www.usenix.org/conference/osdi-02/memory-resource-management-vmware-esx-server}}</ref>  VMware later replaced ESX Server with VMware ESXi, a more lightweight hypervisor architecture that eliminated the Linux-based Console Operating System (COS) used in the original ESX.<ref>{{cite web |title=VMware ESXi is a bare-metal hypervisor that installs directly onto your physical server |url=https://endoflife.date/vmware-esxi |website=endoflife.date |access-date=May 12, 2025}} </ref> 
The physical server typically runs a [[hypervisor]] which is tasked with creating, releasing, and managing the resources of "guest" operating systems, or [[virtual machine]]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 except for those allocated to it by the hypervisor. As a VPS runs its own copy of its operating system, customers have [[superuser]]-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, [[random access memory|RAM]], and disk space.<ref>{{cite web|url=https://www.online-sciences.com/computer/vps-web-hosting-virtual-private-server-advantages-and-disadvantages/ |title=VPS Web Hosting ( Virtual Private Server ) advantages and disadvantages|work=online-sciences.com |date=18 December 2015 |access-date=13 February 2019}}</ref>

There are several approaches to virtualization. In [[Virtualization#Hardware_virtualization|hardware virtualization]], a [[hypervisor]] such as the [[Kernel-based Virtual Machine]] allows each virtual machine (VM) to run its own independent kernel, providing greater isolation from the host system. By contrast, [[Containerization (computing)|container-based virtualization]]—for example [[OpenVZ]]—shares the host kernel among multiple containers. This can improve resource efficiency, but usually offers less isolation and fewer customization options for each instance.<ref name="KVMvsOpenVZ">{{cite web |title=What is a KVM VPS? |url=https://www.liquidweb.com/vps/what-is-kvm-vps/ |website=Liquid Web |access-date=12 May 2025}}</ref>

== Hosting ==
Many companies offer virtual private server hosting or virtual [[dedicated server]] hosting as an extension for [[web hosting]] services. There are several challenges to consider when licensing proprietary software in [[Multitenancy|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&nbsp;Mbit/s, 100&nbsp;Mbit/s, or 1000&nbsp;Mbit/s (with some as high as 10&nbsp;Gbit/s). This means that the customer is theoretically able to use approximately 3&nbsp;TB on 10&nbsp;Mbit/s or up to approximately 300&nbsp;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.

== See also ==
* [[Comparison of platform virtualization software]]
* [[Cloud computing]]
* [[Virtual private cloud]]

== References ==
{{Reflist}}

[[Category:Servers (computing)]]

[[Category:Cloud computing]]