Abstract: In an electronic trading system in which a blockchain managing an electronic trading of a trading target is managed by a plurality of nodes, each of the plurality of nodes includes: a first storage unit storing a distributed ledger of the blockchain; and a second storage unit storing content of the trading target to be concealed as actual data in nodes other than a specific node constituting the blockchain. The distributed ledger stored in the first storage unit is stored in all of the plurality of nodes managing the blockchain and is shared by all of the plurality of nodes. The second storage unit of the specific node among the plurality of nodes stores the actual data of the trading target, sets an access right to the actual data stored in the specific node, and stores the access right in the distributed ledger.

Abstract: A data management system including a plurality of servers each having a processor, a memory, and a storage device, the system receiving and storing data using the plurality of servers and multiplexing the data, wherein the servers are provided with: a first determination unit that determines the consistency of the multiplexed data; a second determination unit that has a greater number of allowable server failures than the first determination unit for determining the consistency of the multiplexed data but a greater minimum number of times of server-to-sever communications for determining the consistency of the data; a combination unit that receives a data consistency determination result from the first determination unit or the second determination unit, and that, if the determination result includes consistency guaranteeing data, outputs the consistency guaranteed data; and a data storage unit that stores the data output by the combination unit.

Abstract: A computer system comprises a plurality of computers for executing a service by using databases constructed of storage areas included in the plurality of computers. Each of the plurality of computers is configured to hold performance management information for managing respective performances of the plurality of computers. The each of the plurality of computers is allocated master data and replicated data of the master data managed by one of the plurality of computers other than the each of the plurality of computers. The computer system comprises a performance information management part configured to update the performance management information; and a cluster configuration management part configured to determine, based on the performance management information, the management range of the master data managed by a computer and a sub-computers configured to hold the replicated data of the master data managed by the computer.

Abstract: A data management system including a plurality of servers each having a processor, a memory, and a storage device, the system receiving and storing data using the plurality of servers and multiplexing the data, wherein the servers are provided with: a first determination unit that determines the consistency of the multiplexed data; a second determination unit that has a greater number of allowable server failures than the first determination unit for determining the consistency of the multiplexed data but a greater minimum number of times of server-to-sever communications for determining the consistency of the data; a combination unit that receives a data consistency determination result from the first determination unit or the second determination unit, and that, if the determination result includes consistency guaranteeing data, outputs the consistency guaranteed data; and a data storage unit that stores the data output by the combination unit.

Abstract: A computer system comprises a plurality of computers for executing a service by using databases constructed of storage areas included in the plurality of computers. Each of the plurality of computers is configured to hold performance management information for managing respective performances of the plurality of computers. The each of the plurality of computers is allocated master data and replicated data of the master data managed by one of the plurality of computers other than the each of the plurality of computers. The computer system comprises a performance information management part configured to update the performance management information; and a cluster configuration management part configured to determine, based on the performance management information, the management range of the master data managed by a computer and a sub-computers configured to hold the replicated data of the master data managed by the computer.