File virtualization is a method of allowing access to stored information on a network. Users of a file virtualization network are able to access files and folders that are located on multiple servers as though they were all in the same place. This lets data be moved without disrupting user access to it. There are two different kinds of file virtualization systems: out-of-band and in-band.
One of the big problems of the modern computerized business world is how to make sure everyone has access to all the information needed to do a job. In order to access this information, workers must know the information's namespace, or its location on a storage device. Data about a project might exist on several different servers located in different buildings or even different countries.
File virtualization is a way for files on different servers to be accessed using a single access key. Instead of accessing an individual server, the user sends a request to the global namespace. The global namespace is a virtual area created by the file virtualization network. It knows where all the files are on every server. When the user sends a request, the global namespace responds by showing the user all the information associated with that access key regardless of which server stores the data.
This system has several advantages over traditional methods of data storage. Most important for the user, all related information appears in the same place, even if half is on a server in New York and the other half is on a server in Moscow. File virtualization also allows network administrators to move data without the user knowing it happened. As long as the global namespace knows where the data is, the user can find it using the same access key.
There are two different kinds of file virtualization systems. Out-of-band systems are based on software. They create a virtual proxy server through which data is accessed. This is an older style of virtualization and only works when all files in the system are of the same type. It has trouble covering large geographic areas as well. Files on an out-of-band system can only be moved when they are not being accessed by users.
In-band systems put a physical access point on the network between the users and the servers. Users send requests to this box to gain access to the files on the servers. This style of virtualization works well with heterogeneous files. It is a newer technology, the main drawback of which is that if the physical access point fails, access to the virtual network is impossible until the box can be replaced.