File server load distribution system and method

• US 6,401,121 B1
• Filed: 11/15/1996
• Issued: 06/04/2002
• Est. Priority Date: 12/26/1995
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Yoshida, Hiroshi, Munaka, Tatsuji
• Primary Examiner(s): Rinehart, Mark H.
• Assistant Examiner(s): Thompson, Marc D.
• Application Number:
  US08/749,499
• Time in Patent Office: 2,027 Days
• Field of Search: 395/182.02, 395/182.04, 395/182.16, 395/200.31, 395/200.33, 395/200.47, 395/200.48, 395/200.49, 395/200.65, 395/200.72, 395/200.7, 395/200.74, 395/674, 395/675, 395/728, 395/729, 395/730, 395/731, 395/732, 395/651, 707/8, 707/201, 707/10
• US Class Current: 709/227
• CPC Class Codes: G06F 16/182 Distributed file systems
• CPC Class Codes: G06F 2209/5019 Workload prediction
• CPC Class Codes: G06F 9/505 considering the load
• CPC Class Codes: G06F 9/5083 Techniques for rebalancing the load in a distributed system
• CPC Class Codes: H04L 67/01 Protocols
• CPC Class Codes: H04L 67/06 specially adapted for file transfer, e.g. file transfer protocol [FTP]
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/10015 Access to distributed or replicated servers, e.g. using brokers
• CPC Class Codes: H04L 67/1008 based on parameters of servers, e.g. available memory or workload monitoring of computer activity G06F11/30
• CPC Class Codes: H04L 67/101 based on network conditions
• CPC Class Codes: H04L 67/1012 based on compliance of requirements or conditions with available server resources
• CPC Class Codes: H04L 67/1023 based on a hash applied to IP addresses or costs
• CPC Class Codes: H04L 67/568 Storing data temporarily at an intermediate stage, e.g. caching
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: H04N 21/23103 using load balancing strategies, e.g. by placing or distributing content on different disks, different memories or different servers storage management G06F3/0604; allocation of resources considering the load in multiprogramming arrangements G06F9/505; techniques for rebalancing the load in a distributed system G06F9/5083; access to distributed or replicated servers, e.g. load balancing, in data networks H04L67/1001
• CPC Class Codes: H04N 21/23116 involving data replication, e.g. over plural servers synchronization of replicated data G06F11/1658; error detection or correction by means of data replication G06F11/2053; replication in distributed file systems G06F16/10; replication in distributed file systems G06F16/27; replication or mirroring of data in data networks H04L67/1095

Abstract

A load distribution system includes a plurality of servers, each having a memory device in which are stored a plurality of data files for transmission to a plurality of client stations, and a control server which is connected to the plurality of servers for controlling the distribution of transmission requests from client stations as loads on the servers by acquiring transmission counts for data files that are transmitted by the plurality of servers, and determining which server should respond to a transmission request as a data transmission server based on which server has a transmitted data count which is the smallest.

Claims

1. A load distribution system for distributing as loads transmission requests for selected data files issued by a plurality of client stations, comprising:

(a) a plurality of servers, each having a memory device in which are stored a plurality of data files, for transmitting requested data files to client stations; and

(b) a control server connected to said plurality of servers, said control server including

calculation means for acquiring a count of data file transmission occurrences by each of said plurality of servers, said count being a current number of transmissions executed by a corresponding server, and

determination means for receiving said transmission requests from said plurality of client stations, and for selecting, as a data transmission server, a server for which a data file transmission count acquired by said calculation means is the smallest.

2. A load distribution system for distributing as loads transmission requests for selected data files issued by a plurality of client stations, comprising:

(a) a plurality of servers, each having a memory device in which are stored a plurality of data files, for transmitting requested data files to client stations; and

(b) a control server connected to said plurality of servers, said control server including

calculation means for acquiring a transmission count for each of said data files that are transmitted by said plurality of servers, and

determination means for receiving said transmission requests from said plurality of client stations, and selecting as a data transmission server, a server for which a transmission count of data files that are requested by said client stations is smallest.

3. A load distribution system for distributing as loads transmission requests for selected data files issued by a plurality of client stations, comprising:

(a) a plurality of servers, each having a memory device in which are stored a plurality of data files, for transmitting requested data files to client stations; and

(b) a control server connected to said plurality of servers, said control server including

calculation means for acquiring load distribution records of said plurality of servers from stored access histories for said plurality of servers, and determination means for receiving transmission requests from said plurality of client stations, and for anticipating future loads for said plurality of servers in consonance with said load records, and for selecting a server as a data transmission server for which anticipated future loads are lowest.

4. A load distribution system according to claim 3, wherein said calculation means calculates a remaining transmission time for data files being transmitted by said plurality of servers, and wherein said determination means employs said load distribution records to anticipate loads up until said remaining transmission time for said data has ended, and selects as a data transmission server a server for which anticipated loads are lowest.

19. A load distribution system according to claim 3, wherein said determination means anticipates whether said future loads will increase or decrease for selecting a data transmission server.

5. A load distribution system for distributing as loads transmission requests for selected data files issued by a plurality of client stations, comprising:

(a) a plurality of servers, each having a memory device in which are stored a plurality of data files, for transmitting requested data files to client stations; and

(b) a control server connected to said plurality of servers, said control server including

determination means for receiving said transmission requests from said plurality of client stations, for copying a data file that is requested by said client stations from a server storing said data file to a server that does not contain said data file, and for selecting said server to which said data file is copied as a data transmission server.

6. A load distribution system according to claim 5, wherein said determination means permits said server to which data files are copied to transmit stored data files in parallel with execution of copying of data files to said server.

7. A load distribution system according to claim 5, wherein said determination means uses maximum transmitted data counts and maximum transmission counts of identical data for said plurality of servers as threshold values for copy execution by said plurality of servers, and employs said threshold values to determine whether or not said data files are to be copied.

8. A load distribution system according to claim 5, wherein said determination means uses a threshold value, for each item of said data, that indicates a maximum count for data copies to be stored, and employs said threshold value to determine whether or not copying of said data files is to be executed.

9. A load distribution system according to claim 5, wherein said determination means verifies a remaining storage capacity for each of said memory devices of said plurality of servers, and selects said server to which said data files are to be copied in accordance with said remaining storage capacity.

10. A load distribution system according to claim 9, wherein said control server further comprises calculation means for acquiring a transmission count for each of said data files that each of said plurality of servers transmits, and wherein, when said remaining storage capacity for said memory devices of each of said plurality of servers is smaller than the size of said data file to be copied, said determination means deletes a data file from a selected server for which a transmission count is smallest.

11. A load distribution system according to claim 10, further comprising a library server having a memory device in which a plurality of data files are stored, wherein before deletion of a data file from a selected server said determination means copies that data file to said library server.

12. A load distribution system according to claim 5, wherein said control server further comprises calculation means for acquiring a load distribution record for a predetermined one of said plurality of servers from transmission access histories for said plurality of servers, and wherein, in accordance with said load distribution records, said determination means anticipates loads for said plurality of servers caused by copying operations, and selects as a copy destination server a server that has an anticipated load that is lowest.

13. A load distribution system comprising:

(a) a plurality of servers, each having a memory device in which is stored a plurality of data files, for transmitting said plurality of data files to client stations; and

(b) a control server connected to said plurality of servers, said control server including

calculation means for calculating a bandwidth that indicates a bit transmission rate per unit of time for data transmitted by each of said plurality of servers, and

determination means for receiving from said client stations transmission requests for particular data files, and for selecting a server as a data transmission server which has a bandwidth that is smallest.

14. A load distribution method for distributing requests for data transmission among a plurality of servers, comprising the steps of:

acquiring counts of data that are transmitted to client stations by each of said plurality of servers, each of said counts being a current number of transmissions executed by a corresponding server;

receiving a transmission request for data from said client stations; and

selecting as a data transmission server for responding to said transmission request a server for which a data transmission count is smallest.

15. A load distribution method for distributing requests for data transmission among a plurality of servers, comprising the steps of:

acquiring a data transmission count for data being transmitted by each of said plurality of servers;

receiving a transmission request for data from said client stations; and

selecting from among said plurality of servers that are transmitting said data that are requested by said client stations, a server for which said transmission count for said data is smallest.

16. A load distribution method for distributing requests for data transmission among a plurality of servers, comprising the steps of:

acquiring bandwidths that each indicate a bit transmission rate per unit of time for data that are transmitted to client stations by said plurality of servers;

receiving transmission requests for said data from said client stations; and

selecting a server as a data transmission server which has a bandwidth that is smallest.

17. A load distribution system, comprising:

(a) a plurality of servers, each having a memory device in which is stored a plurality of data files, for transmitting requested data files to a plurality of client stations; and

(b) a control server connected to said plurality of servers, said control server including

calculation means for calculating available space in a bandwidth that indicates a bit transmission rate per unit of time for data transmitted by each of said plurality of servers, and

determination means for receiving from said client stations transmission requests for particular data files, and for selecting as a data transmission server from said plurality of servers a server that has the most available space in said bandwidth.

18. A load distribution method for distributing requests for data transmission among a plurality of servers, comprising the steps of:

acquiring available space in a bandwidth that indicates a bit transmission rate per unit of time for data that are transmitted to a plurality of client stations by each of said plurality of servers;

receiving transmission requests for said data from said client stations; and

selecting as a data transmission server from said plurality of servers a server that has the most available space in said bandwidth.