FILE STORAGE SYSTEM, FILE STORING METHOD AND FILE SEARCHING METHOD THEREIN

• US 20080082525A1
• Filed: 09/25/2007
• Published: 04/03/2008
• Est. Priority Date: 09/29/2006
• Status: Active Grant

• Current Assignee: Electronics and Telecommunications Research Institute
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: CHA, Myung Hoon, KIM, Myung Joon, KIM, Hong Yeon, KIM, June
• Granted Patent: US 7,933,938 B2
• Time in Patent Office: Days
• US Class Current: 707/5
• CPC Class Codes: G06F 16/14 Details of searching files based on file metadata
• CPC Class Codes: G06F 16/1737 for reducing power consumption or coping with limited storage space, e.g. in mobile devices saving storage space on storage devices G06F3/0608; power saving in storage systems G06F3/0625

Abstract

A file storage system, a file storing method, and a file searching method. In the file storing method, a single file to be stored is classified into at least one or more objects, and the classified objects are classified into pages with a serial number. One storage device to record the file is selected among a plurality of storage devices connected through a network. One object is allocated to the selected storage device. Pages configuring the file of the object allocated to the selected storage device are stored. When all pages of the file are not stored, the remaining pages are stored by allocating new object to a new storage device. Metadata for managing information about the storage of the file is set. Accordingly, the file can be stored over several disks. In addition, the overall system performance can be increased by setting the file information in the object metadata simply using the least resources.

Claims

1. A file storing method of a file storage system, comprising:

classifying a single file to be stored into at least one or more objects;

classifying the classified objects into pages with a serial number;

selecting one storage device to record the file among a plurality of storage devices connected through a network;

allocating one object to the selected storage device;

storing pages configuring the file of the object allocated to the selected storage device;

storing the remaining pages by allocating new object to a new storage device when all pages of the file are not stored; and

setting metadata of the file for managing information about the storage of the file.

2. The file storing method according to claim 1, wherein the step of setting metadata of the file for managing information comprises:

configuring the metadata of the file by adding metadata of the object allocated in each storage device storing the pages;

setting fields representing information necessary to store the file in each storage device storing the pages; and

updating information of the object containing the stored page with the metadata of the object, when the page is stored.

3. The file storing method according to claim 2, wherein the step of updating information of the object containing the stored page comprises:

when the page is stored in the selected storage device, setting the page number to be stored to a page information field within metadata of a first object added to the metadata of the file; and

when all pages of the file are not stored, setting the remaining page numbers to a page information field within metadata of a second object added to the metadata of the file.

4. The file storing method according to claim 3, further comprising setting the page number to an overflow field within the metadata of the second object, when the page number is included in an expression range of the page information field within the metadata of the first object.

5. The file storing method according to claim 2, wherein the metadata of the object comprises a storage device information field (disk ID), an object information field (object ID), a page information field (from_offset, to_offset), and an overflow information field (overflow), the page information being classified by a smallest page number (from_offset) and a largest page number (to_offset) among the pages stored in one storage device.

6. The file storing method according to claim 5, wherein when the remaining pages of the file that are not recorded are included in the range of the page information, the overflow field expresses page information about the remaining pages as ((overflow_count), (from₁, to₁), (from₂, to₂), . . . , (from_n, to_n)).

7. A file searching method of a file storage system, comprising:

checking if a file to be stored is previously stored by using a file name in directory information of the file;

when the file is previously stored, searching a storage device which has the page to be inputted/outputted by using the page number of the page to be inputted/outputted; and

reading or modifying the file by transferring input/output signals to the searched storage device.

8. The file searching method according to claim 7, wherein the step of searching the storage device comprises:

retrieving a latest object entry in metadata of a file for managing information of the file to be stored;

retrieving the page number of the page to be inputted/outputted in an overflow field within an object metadata of the retrieved object entry;

when the page number does not exist in the overflow field, retrieving the page number in a page information field within the object metadata of the retrieved object entry; and

when the page number is found, returning a number of a storage device containing the retrieved object entry.

9. The file searching method according to claim 8, further comprising:

retrieving a previously set object entry when the page number is not found;

retrieving the page number in the object metadata of the previous object entry; and

returning the number of the storage device containing the previous object entry when the page number is found.

10. The file searching method according to claim 9, further comprising reporting that the page does not exist when the page number is not found in all previously set object entries.

11. The file searching method according to claim 8, wherein the metadata of the file comprises fields expressing storage information about a single file stored over a plurality of storage devices, the metadata of the file containing metadata of objects as many as number of the storage devices storing the single file.

12. The file searching method according to claim 8, wherein the metadata of the object comprises a storage device information field (disk ID), an object information field (object ID), a page information field (from_offset, to_offset), and an overflow information field (overflow), the page information being classified by a smallest page number (from_offset) and a largest page number (to_offset) among the pages stored in one storage device.

13. The file searching method according to claim 12, wherein when the remaining pages of the file that are not recorded are included in the range of the page information, the overflow field expresses page information about the remaining pages as ((overflow_count), (from₁, to₁), (from₂, to₂), . . . , (from_n, to_n)).

14. A file storage system comprising:

a file generator for classifying a single file to be stored into at least one object, and classifying the object into pages with a serial number;

a plurality of storage devices, connected through a network and to which the at least one object is allocated, for storing the pages configuring the file of the allocated object;

a controller for selecting one storage device to record the file among the plurality of storage devices and allocating one object to the selected storage device; and

a file storage information manager for setting metadata of a file for managing information about storage of the file.

15. The file storage system according to claim 14, wherein the controller allocates a new object to a new storage device when all pages of the file are not stored.

16. The file storage system according to claim 14, wherein when the previously stored file is retrieved, the controller searches a storage device storing a page to be inputted/outputted by using the page number, and reads or modifies the file by transferring input/output signals to the searched storage device.

17. The file storage system according to claim 16, wherein the controller retrieves page numbers from a latest object entry to an oldest object entry in sequence, the page number being retrieved in an overflow field and a page field within metadata of a corresponding object entry.

18. The file storage system according to claim 14, wherein the file storage information manager sets fields expressing storage information about a single file stored over a plurality of storage devices, the metadata containing metadata of objects as many as number of the storage devices storing the single file, the information about the object containing the stored page updating in the metadata of the file when a single page is stored.

19. The file storage system according to claim 18, wherein the file storage information manager sets the stored page number to a page information field within metadata of a first object when the page is stored in the selected storage device, and sets the remaining page numbers to a page information field within metadata of a second object when all pages of the file are not stored.

20. The file storage system according to claim 14 or 19, wherein the metadata of the object comprises a storage device information field (disk ID), an object information field (object ID), a page information field (from_offset, to_offset), and an overflow information field (overflow), the page information being classified by a smallest page number (from_offset) and a largest page number (to_offset) among the pages stored in one storage device.

21. The file storage system according to claim 20, wherein when the remaining pages of the file that are not recorded are included in the range of the page information, the overflow field expresses page information about the remaining pages as ((overflow_count), (from₁, to₁), (from₂, to₂), . . . , (from_n, to_n).