Client-server system with parity storage

• US 5,905,847 A
• Filed: 02/06/1997
• Issued: 05/18/1999
• Est. Priority Date: 03/30/1995
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation), Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Nakamura, Shunichiro, Kobayashi, Tsuyoshi, Yamaguchi, Tomohisa, Minemura, Harumi
• Primary Examiner(s): Chin, Tommy P.
• Assistant Examiner(s): LEE, Y YOUNG
• Application Number:
  US08/796,538
• Time in Patent Office: 831 Days
• Field of Search: 386/113, 386/46, 386/45, 386/125, 348/7, 348/12, 348/13, 455/5.1, 395/200.08
• US Class Current: 386/265
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems
• CPC Class Codes: G06F 11/16 Error detection or correction of the data by redundancy in hardware
• CPC Class Codes: G06F 11/2087 with a common controller
• CPC Class Codes: G06F 2211/1028 Distributed, i.e. distributed RAID systems with parity
• CPC Class Codes: G06F 2211/1057 Parity-multiple bits-RAID6, i.e. RAID 6 implementations
• CPC Class Codes: H04N 21/2182 involving memory arrays, e.g. RAID disk arrays RAID arrays per se G06F3/0689; use of parity to protect data in RAID systems G06F11/1008
• CPC Class Codes: H04N 7/17336 Handling of requests in head-ends

Abstract

A client-server system which improves efficiency of each server by distributing loads to a plurality of servers having a plurality of storages for sequentially storing data which are distributed in each of the plurality of storages; a plurality of servers, each of which is connected to the plurality of storages, for accessing the data distributed and stored in each of the plurality of storages; an administration apparatus which is connected to the plurality of servers for administrating the data sequentially stored in the plurality of storages, and the plurality of servers; and a client which is connected to both the administration apparatus and the plurality of servers, the clients specifies a server which is connected to a storage where a head block of the data is stored by inquiring to the administration apparatus, and accesses the data in the plurality of servers according to the order of the data storage sequence from the specified server.

Claims

1. A client-server system comprising:

(a) a plurality of storage devices for storing data wherein said data is distributed in said plurality of storage devices;

(b) a plurality of servers, each of which is connected to a portion of said plurality of storage devices for accessing said data;

(c) an administration apparatus which is connected to said plurality of servers for administrating said data and said plurality of servers; and

(d) a client which is connected to both said administration apparatus and said plurality of servers, wherein said client comprises;

(d1) an access demand means for specifying a server, identified by said administration apparatus, which is connected to a storage device where a head block of said data is stored, and for accessing said data through said plurality of servers according to an order in which said data is distributed in said plurality of storage devices after said specified server,

wherein each of said plurality of servers comprises;

an intra-server parity generation means for generating parities from data stored in a portion of said plurality of storage devices connected to a respective server, and for storing said generated parities into one of said plurality of storage devices connected to said respective server;

a parity storage device for storing said parities, wherein said intra-server parity generation means stores said generated parities into said parity storage device; and

an intra-server restoration means for restoring data which are stored in an inaccessible storage device, using data which are stored in accessible storage devices and parities which are stored in an accessible parity storage device connected to a respective server connected to said inaccessible storage device, when any one of said plurality of storage devices becomes inaccessible.