Distributed File System - Transparency

Transparency

Transparency is usually built into distributed file systems so that files accessed over the network can be treated the same as files on local disk by programs and users. The multiplicity and dispersion of servers and storage devices are thus made invisible. It is up to the network file system to locate the files and to arrange for the transport of the data.

• Access transparency is that clients are unaware that files are distributed and can access them in the same way as local files are accessed.
• Location transparency A consistent name space exists encompassing local as well as remote files. The name of a file does not give its location.
• Concurrency transparency All clients have the same view of the state of the file system. This means that if one process is modifying a file, any other processes on the same system or remote systems that are accessing the files will see the modifications in a coherent manner.
• Failure transparency The client and client programs should operate correctly after a server failure.
• Heterogeneity File service should be provided across different hardware and operating system platforms.
• Scalability The file system should work well in small environments (1 machine, a dozen machines) and also scale gracefully to huge ones (hundreds through tens of thousands of systems).
• Replication transparency To support scalability, we may wish to replicate files across multiple servers. Clients should be unaware of this.
• Migration transparency Files should be able to move around without the client's knowledge.