File sharing method and file sharing system

• US 8,250,176 B2
• Filed: 04/23/2007
• Issued: 08/21/2012
• Est. Priority Date: 04/25/2006
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Ohtani, Atsuhisa
• Primary Examiner(s): Patel, Haresh N
• Assistant Examiner(s): LE, CHAU D
• Application Number:
  US11/785,947
• Publication Number:
  US 20070250594A1
• Time in Patent Office: 1,947 Days
• Field of Search: 709/218, 709/217, 709/219
• US Class Current: 709/218
• CPC Class Codes: G06F 16/176 Support for shared access to files; File sharing support
• CPC Class Codes: G06F 16/188 Virtual file systems

Abstract

System and method to perform rapid I/O processing for a large file reducing load on a server computer and a network. The client computer accesses a disk device directly to perform input/output processing relating to a file operation through a channel switch based on real file information obtained by the client computer from a parent server computer upon a file-open operation. Further, a child server computer manages the disk device, which enables different real files in a same virtual file to be processed an I/O at the same time by a plurality of client computers.

Claims

1. A file sharing system comprising:

a plurality of disk devices;

a plurality of child server computers, each of the plurality of child server computers manages one of the disk devices;

a parent server computer configured to manage the plurality of child server computers; and

a plurality of client computers, wherein

the disk devices store a large divided file,

the plurality of client computers, the plurality of child server computers, and the parent server computer are connected through a network,

the plurality of disk devices, each of the plurality of client computers, and each of the plurality of child server computers are connected through a channel switch so that at least each of the plurality of client computers can directly access the plurality of disk device; and

the parent server computer comprising;

a child server managing unit configured to create real file information, wherein the created real file information specifies a structure of a real file system in each of the disk devices, a structure of a virtual file system over the real file system, and a stored position of a real file in the virtual file system, and

a file management database configured to store created real file information,

each of the plurality of client computers comprising;

a real file information obtaining unit configured to send a request to the parent server computer through the network so as to obtain real file information corresponding to a target file from the parent server computer upon a file-open operation;

a real file information registering unit configured to register the real file information obtained by the real file information obtaining unit in a file management table within the respective one of the plurality of client computers; and

an I/O requesting unit comprising the functions of;

determining whether the real file information corresponding to the target file is stored or not in the file management table upon the file-open operation;

sending a request of input/output processing directly to the corresponding child server computer based on the real file information stored in the file management table in a case the target file is stored in the file management table;

sending a request to the parent server computer through the network so as to obtain the real file information corresponding to the target file from the parent server computer in a case the target file is not stored in the file management table; and

sending a request of inputting/outputting processing directly to the corresponding child server computer based on the obtained real file information so as to perform input/output processing relating to a file operation accessing directly the disk devices through the channel switch according to block I/O information sent by the child server computer.

2. A file sharing method with each of a plurality of child server computers managing a plurality of disk devices individually, a parent server computer managing the plurality of child server computers, and a plurality of client computers are connected communicably, and a large file is divided to be stored in the disk devices, the method comprising the steps of:

connecting the plurality of client computers, the plurality of child server computers and the parent server computer through a network; and

the plurality of disk devices, the respective client computers, and the respective child server computers are connected through a channel switch so that at least each of the plurality of client computers can directly access the plurality of disk devices; and

registering in advance real file information for specifying a structure of a real file system in each of the plurality of disk devices, a structure of a virtual file system over the real file systems, and stored position of the real file in the virtual file system, into the parent server computer as a file management database;

upon file-open operation by a respective client computer, determining whether or not the real file information corresponding to a target file is stored in a file management table included by the respective client computer;

starting input/output processing relating to file operation by sending a request for input/output processing directly to the corresponding child server computer when the real file information is stored in the file management table; and

obtaining the real file information corresponding to the target file from the parent server computer by sending a request to the parent computer server through the network when the real file information is not stored in the file management table;

storing the obtained real file information in the file management table; and

directly accessing, by the respective client computer, the disk device through the channel switch so as to perform input/output processing relating to the file operation based on the real file information.

3. The file sharing method, as claimed in claim 2, wherein the respective client computer requests from the parent server computer of the real file, information of a real file continuing from the real file, when the real file termination is detected in the disk device during the input/output processing relating to the file operation by the respective client computer to the respective disk device based on the real file information.