Virtual file system

A method for creating a virtual file system that provides clients access to files stored on a plurality of underlying file systems hosted on one or more file servers, comprising:

• exporting a virtual file system view to a client comprising a virtual directory and file hierarchy that includes a virtual pathnames for each data file that may be accessed by the client;
• maintaining mapping information that maps the virtual pathname for each file to a file server and physical pathname under which the file is stored on that file server;
• enabling a data file to be accessed by the client through referencing the file by its virtual pathname;
• providing a client-side filter that intercepts file system access requests made by the client that reference the virtual pathname to access a file;
• and
• routing the file system request to the server and pathname under which the file is actually stored based on the mapping information for the file.

A method for providing a virtual file system that aggregates storage space that is partitioned across a plurality of underlying file systems hosted on one or more file servers, comprising:

• enabling clients to create a virtual directory and file name hierarchy in which data files that may be accessed via the virtual file system are identified by a corresponding virtual pathname;
• storing the data files on one or more slave logical volumes hosted by said plurality of underlying file systems;
• and
• providing a software file system virtualization layer including both client-side and server-side software components that cooperatively enable clients to access data files stored in the single virtual storage space through reference to the virtual pathnames for those data files by intercepting client file system requests and routing the file system request to the actual file server and pathname under which the file is stored.

A virtual file system comprising:

• a computer network that connects a plurality of clients to a plurality of file servers;
• a plurality of underlying file systems hosted on the plurality of servers in which a plurality of data files are stored;
• a server-side software virtualization component running on each file server;
• a client-side software virtualization component running on each client,
• wherein the client-side and server-side software virtualization components cooperatively enable the clients to create a virtual directory and file name hierarchy including a virtual pathname for each data file that is used to access that data file by intercepting client file system requests that reference the virtual pathname of the data file and routing the file system request to the actual file server and pathname under which the data file is stored.