System and method for virtualizing a distributed network storage as a single-view file system

• US 20030140051A1
• Filed: 08/16/2002
• Published: 07/24/2003
• Est. Priority Date: 01/23/2002
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Fujiwara, Shinji, Uemura, Tetsuya, Sagawa, Nobutoshi, Odawara, Hiroaki
• Granted Patent: US 7,587,426 B2
• Time in Patent Office: Days
• US Class Current: 707/100
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/1023 based on a hash applied to IP addresses or costs
• CPC Class Codes: H04L 67/1097 for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS]

Abstract

The invention relates to a method of virtualizing a plurality of network storages into a single-view file system for a client and obtains information about an object'"'"'s storage location without inquiring of a resource manager. The method determines a network storage that should store an object based on a hash value generated from a logical identifier for the object to be accessed. While accessing the object, the method computes the hash value for the object'"'"'s logical identifier to determine a network storage that should process an access request. Consequently, the method eliminates the need to inquire the object'"'"'s storage location when the access request is issued. Further, the method eliminates the need to maintain the object'"'"'s storage location when the number of servers is increased or decreased, thus providing easy management.

Claims

1. A network storage virtualization method in a network storage system comprising a plurality of network storage devices in which the method allows a client connected via a network to access the plurality of network storage devices as one virtual network storage system, wherein a network storage for storing objects is determined based on a value uniquely determined from a logical identifier for an object to be accessed by the client.

2. The network storage virtualization method according to claim 1, wherein the object is a file or a directory and uses a file'"'"'s or directory'"'"'s full path name as the logical identifier.

3. The network storage virtualization method according to claim 1, wherein the network storage for storing objects is determined based on a value uniquely determined from an access location and a hash value of a logical identifier for an object to be accessed by the client.

4. A network storage virtualization method in a network storage system comprising a plurality of network storage devices and a network device for connecting the plurality of network storage devices with an external network, wherein the network device accepts an access request for a storage from a client supplying an input via the external network and sends the access request to the plurality of network storage devices;

each network storage device determines whether or not the network storage device itself matches a network storage device determined by a hash function using, as an argument, a logical identifier for an object as an access target of an access request sent from the network device; and

the access request is processed when a match is found.

5. The network storage virtualization method according to claim 4, further including a step of transferring the access request to a network storage device determined by the hash function when no match is found as a result of the determination.

6. A method of generating handle information for objects in a network storage system comprising a plurality of network storage devices and providing a capability of allowing a client connected via a network to access the plurality of network storage devices as one virtual network storage, wherein:

when the client requests to generate handle information used for an access to an object stored in a network storage, the method computes a hash value of a logical identifier for an object to be accessed and returns handle information embedded with the hash value as handle information for the object to be accessed.

7. The method of generating handle information for objects according to claim 6, wherein the hash value is computed from a hash value already embedded in handle information for an object higher than the object to be accessed and from a path name specifying the object to be accessed.