A virtual private server (VPS) is a virtual machine sold as a service by an Internet hosting service. The dedicated virtual server (VDS) also has a similar meaning.
A VPS runs its own copy of an operating system (OS), and clients can have superuser level access to that instance of the operating system, so they can install almost any software running on that OS. For many purposes, they are functionally equivalent to a dedicated physical server and, being defined by software, can be created and configured much more easily. They are priced much lower than an equivalent physical server. However, since they share the underlying physical hardware with other VPS, performance may be lower, depending on the workload of any other running virtual machine.
The force that drives server virtualization is similar to that which led to the development of timeshare and multiprogramming in the past. Although resources are still shared, as in the timeshare model, virtualization provides a higher level of security, depending on the type of virtualization used, since individual virtual servers are mostly isolated from each other and can execute their own rights. complete. operating system that can be restarted independently as a virtual instance.
Partitioning a single server to appear as multiple servers has been increasingly common in microcomputers since the launch of VMware ESX Server in 2001. The physical server generally runs a hypervisor that has the task of creating, freeing and managing the resources of "guest" operating systems. or virtual machines. These guest operating systems are assigned a portion of the resources of the physical server, generally in a way in which the guest is not aware of any other physical resources, except those assigned by the hypervisor. As a VPS runs its own copy of its operating system, customers have superuser level access to that instance of the operating system and can install almost any software running on the operating system, however due to the number of virtualization clients Normally running on a single machine, a VPS generally has limited processor time, RAM and disk space.
advantages and disadvantages
Ultimately, it is used to decrease hardware costs by condensing a failover cluster on a single machine. In this way, costs are drastically reduced while providing the same services. Server functions and functions are generally designed to work in isolation. For example, Windows Server 2019 requires a certification authority and a domain controller to exist on separate servers with separate instances of Windows Server. This is because the additional functions and features add areas of possible failure, as well as add visible security risks (placing a certification authority on a domain controller raises the potential for root access to the root certificate). This directly motivates the demand for virtual private servers to retain conflicting server roles and features on a single hosting machine. In addition, the advent of encrypted virtual machine networks reduces transfer risks that might otherwise have discouraged the use of VPS as a legitimate hosting server.
Many companies offer virtual private server hosting or virtual dedicated server servers as an extension for web hosting services. There are several challenges to consider when licensing proprietary software in virtual environments of multiple tenants.
With unmanaged or self-managed hosting, the client must manage its own server instance.
Unmeasured hosting is generally offered without limit on the amount of data transferred on a fixed bandwidth line. In general, unmeasured 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, in theory, the customer can use ~ 3 TB at 10 Mbit / s or up to ~ 300 TB on a line of 1000 Mbit / s per month, although in practice the values will be significantly lower. On a virtual private server, this will be shared bandwidth and a fair use policy should be involved.