NAS WITH WORM FUNCTION

• US 20070220205A1
• Filed: 05/22/2007
• Published: 09/20/2007
• Est. Priority Date: 05/14/2004
• Status: Abandoned Application

• Current Assignee: Koji Sonoda, Takahiro Nakano, Yoji Nakatani
• Original Assignee: Koji Sonoda, Takahiro Nakano, Yoji Nakatani
• Inventors: Nakatani, Yoji, Sonoda, Koji, Nakano, Takahiro
• Application Number:
  US11/751,781
• Publication Number:
  US 20070220205A1
• Time in Patent Office: Days
• US Class Current: 711/114
• CPC Class Codes: G06F 3/0622 in relation to access
• CPC Class Codes: G06F 3/0637 Permissions
• CPC Class Codes: G06F 3/0683 Plurality of storage devices

Abstract

A network storage system accessible by a computer, including worm functions.

Claims

1. A storage system accessible by a computer, comprising:

a disk drive unit comprised of plural logical devices;

a memory module which stores information about the disk drive unit;

a first controller comprised of an interface which provides a file system to the computer to facilitate access of files by the computer; and

a second controller which receives access requests from the computer, wherein;

the first and second controllers, when a write request is made by the computer, looks up in the memory module for information on a logical target device that is a target of the write request and, when the logical target device is set to unwritable, inform to the computer that the logical target device is set to unwritable;

the memory module stores a logical unit table which indicates an association between the logical target device and an allocated logical unit allocated to the logical target device;

where the allocated logical unit allocated to the logical target device is accessible by the computer using the file system;

wherein the interface;

stores a mount table indicating which logical unit is mounted to the file system and indicating whether a write in the logical unit is possible; and

stores a map table indicating an association between the logical target device and the allocated logical unit allocated to the logical target device; and

wherein the interface;

obtains a list of files that are not accessed for a predetermined period, referring to meta-information held in the meta logical units for which a first attribute is set;

creates a Universal Disk Format image containing files on the list of files;

secures a logical targeted device that is capable of storing the Universal Disk Format image;

judges whether or not any logical unit is allocated to the secured logical targeted device;

searches, when no logical unit is allocated to the secured logical targeted device, for a logical unit that is not assigned to any logical device from among logical units in which a third attribute is set, using information stored in the memory module;

obtains, when no logical unit is found that is not assigned to any logical device, information of an oldest logical unit that has not been accessed for a longest period, from among the logical units in which the third attribute is set;

unmounts the oldest logical unit for which the information is obtained off the file system;

instructs to the first controller to allocate at least a portion of the unmounted logical unit as a new logical device;

reflects a result of the allocating to the information about the map table, the information being stored in the memory module;

specifies the logical unit to store the created Universal Disk Format image in the new logical device to which the logical unit is allocated; and

sets information on the new logical device that stores the Universal Disk Format image to unwritable, the information being stored in the memory module.