Hosting denotes providing disk space for the physical placement of information on a server which is a constant part of a network (usually the Internet). The server may belong either to the company that is providing the service or to the client. In the latter case, the service is called co-location.

At a minimum, the term hosting is usually understood to mean the service of placing the files of a site on a server on which the software necessary for handling queries regarding these files (Web server) is active. Hosting generally includes the provision of postal correspondence, databases, DNS, file storage, etc., and also of supporting the functioning of the corresponding services.

The hosting of databases, the placement of files, the hosting of e-mail, and DNS services may be provided separately as independent services or they may be included in the overall service.

One of the most important criteria for selecting a hosting service is the operating system that is used since this will determine the software that will support the functionality of a service.

In describing a hosting service, one important aspect to note is the availability of services or possibilities:
  • supporting CGI/Perl, PHP, Python, ASP, Ruby;
  • supporting .htaccess (for Apache);
  • supporting databases.

  • Also important are the modules that have been set up for each of the possibilities.

    Hosting as a service may be compared and described on the basis of quantitative limits:
  • the amount of disk space;
  • the amount of monthly traffic;
  • the number of sites that can fit within the framework of one account;
  • the number of FTP users;
  • the number of e-mail boxes and the amount of space allocated for e-mail;
  • the number of databases and the amount of space for databases;
  • the number of simultaneous processes per user;
  • the amount of RAM, and the maximum execution time allocated to each user process;

  • and on the basis of qualitative limits:
  • unused CPU resources, RAM, which affect the speed of the server;
  • the carrying capacity of the channels, which influences the downloading of information.

  • Some paid hosting companies offer a free test for a specific period, at the end of which the user must decide whether that hosting company is appropriate for him, and whether it makes sense to pay for long periods. As a rule, such tests are provided only to owners of the second-level domains, avoiding speculation with testing accounts. In addition to paid hosting services, there are also non-paid hosting companies, which support the majority of the aforementioned Web technologies.

    Hosting is often divided into paid and unpaid kinds, reflecting the way it is provided. Usually, a company that provides unpaid hosting earns money through putting advertisements on pages that are placed on it. Unpaid hosting, as a rule, is slower than the paid variety, offers only the basic services, and is sometimes unreliable (i.e., it can shut down). Private persons use unpaid hosting services for their personal pages in the initial stages of development. Public organizations may use both paid as well as unpaid hosting services. Commercial organizations almost always use paid hosting services.

    In addition it is also possible to distinguish hosting services according to the type of resource that is made available:
  • virtual hosting means providing space on the disk for placing websites. Thus, a single environment is created for executing Web services for many users, the resources being allocated among all the users on one server, where it is possible to place from 50 to 1000 users. Small, inexpensive hosting providers often ignore safety concerns and don’t place limits on the privileges of users, thus allowing one user on the server to have access to the sites of hundreds of other users. With the larger and more expensive providers, this problem is generally resolved;
  • a virtual dedicated server (VPS or VDS) provides disk space, a portion of the general memory, and server processor time. To the user it looks just like a dedicated server, but several virtual servers are physically placed on one real server. This service is designed for projects of medium difficulty. Since it is impossible to clearly distinguish all the resources of a server (specifically I/O operations, network card resources, etc.), and many VPS providers sell more resources than exist on the server, in the hope that the client will not fully use the potential allocated to him, often the declared capacity of a VPS server does not reflect the real capacity;
  • a dedicated server provides the server as a whole. This is used for realizing non-standard tasks (services), and also for placing "difficult" web projects that cannot coexist on one server with other projects and that require for themselves all the resources of the server;
  • co-location denotes providing space in the datacenter of the provider for the hardware of the client (usually through being mounted on a support) and connecting it to the Internet.