Distributed File System The sharing of stored information is perhaps the most important aspect of distributed resources sharing. But the requirements for the sharing without or local networks and intranet lead to a need for a different type of service – one that support the persistent storage of data and programs of all types on behalf of clients and the consistent distribution of  up-to-date data.   Ideally, in a distribute of file system can be stored at any machine ( or computer) and the computation can be performed at any machine (i.e. the machines are peers).     The two important services presents the distribution file system are the name server and cache management.   Mechanism for Building Distributed File System: Mounting Caching Hints Bulk Data Transistor Encryption     Mounting: A mount mechanism allows the binding together of different file name spaces to form a single hierarchically structured name space. A name space can be bounded to or mounted at an internal node or a leaf node of a name space free. A node onto which a name space is mounted as known as a mount post.     Caching: Caching is commonly, employed in distributed file system to reduce delay in the accessing of data. In file caching, a copy of data is stored at a remote file server is brought to the client when referenced by the client.   Hints: Caching improves files system performance by reducing the delay in accessing data. However, when multiple clients cache and modify shared data, the problem of cache consistency arises. Specifically, it must be guaranteed that the cached data is valid and that a copy of the data-recently updated in some other client or in the file server-does not exist.