What is clustered hosting
Shared hosting seams about to exhaust its resource potential. Web users are most unlikely to share server power with thousands of users at shared environment. Just one "fat" web site might overload the system and get a server down; meanwhile one site is creaming others are out of the game. Alternatively to shared web hosting uses were offered to use VPS hosting, dedicated hosting etc., i.e. pay more and be happy to get your own virtual private server. Seams not bad, hah? But still : technologies move forward and it's awesome! Its evolution resulted in a new hosting class - clustered hosting.
What? Clustered hosting? What is clustered hosting? Who needs it? "Cluster" comes not far, than hosters PR!
Well, if comes to the point in the computing there are several meaning of the term cluster . Clustered hosting is an server architecture solution. So, clustered hosting means an operating group of servers linked into one body with a purpose to organically maintain security, safety and reliability of user's data. Each server within a cluster is able to replace its "brothers" at any time as their work is completely duplicated. It's obvious to say that in the computer world clustering functionality is based on the "un pour tous, tous pour un" concept. Site hosted on a clustered base are pretty tough and fail-safe. These sites are always up and available.
There are several ways to manage cluster. Hope these tips will help you learn what clustered hosting is and how it works.
First way to manage clustered hosting is assigning main services to individual physical server; that is separate MySQL server, separate mail server, separate web server etc. In general the scheme is clear. From this point of view each server handles only one-type tasks without any suffer and overloads. But this way to manage cluster has one little weakness -server links. What if one little glitch happens to MySQL service: True, all sites go to rest:
Second way. Install special software at all servers which shares jobs between clustered servers. Some open source software is available at SourceForge. Let's say our cluster is built from 2 servers with all necessary software installed (control panel software, DB service, mail service, FTP service etc.). When the cluster receives a request - it's received by two servers. Due to internal server interaction within a cluster the request is handled by a server which is processing less tasks at the moment. In such a way server load is balanced immediately. When one server goes down, its functions are duplicated by another one, because data is stored on two servers.
The third way to manage cluster is using external switches. This scheme assumes that when a user sends a request, a switch handles it and passes it to the server which will process it. In such a way a switch balances cluster load. When one server "goes to sleep" a switch sends all requests to the working server, which, actually can cope with all jobs.
Way no. four: managing cluster is also possible with using crossover cable links. In this case servers are clustered due to a special connections between servers themselves. It requires special software. There is no need to user extra hardware and external devices, however.
For all external users cluster appears are a single server with a static IP address. No matter what kind of cluster realization is chosen it's definitely the next stage hosting solution especially for projects with high demands. Price for clustered hosting varies from $10 to $100+ per month. It's pretty reasonable price if you pay for safety, reliability and security.