摘要:
A high availability database system, subject to a failure causing data corruption in the active server system, may recover valid data prior to the corruption, and use the protected and recovered data to effect a failover. At the time T1 when a stand-by computer system detects the occurrence of a failure, a pair split is done to the data area to protect the data area time T0, just before the occurrence of the failure, and another pair split is done to the log area at the time, where the log area is corrupted or a time T3, where the failover is to take effect without corrupting data, to protect the log area containing data at a given time between time TO and time T3. By using the data and log areas thus protected, the stand-by computer system may take over valid data and log areas of the given time to perform a failover.
摘要:
A method for duplicating transactions in a disaster recover system is disclosed. In this method, transactions and queries input to a primary database system are copied to a secondary database system and both database systems execute the queries and save the results permanently to each database, thereby maintaining duplicated data. When executing a query on the primary database system, if the query is a commit, the primary system simultaneously copies uncopied queries placed in a queue to the secondary database system and then executes the query. By using this processing procedure, the invention realizes a disaster recovery system which carries out copying transactions from one site to another site without losing the transactions, while reducing the influence of copy operation on the transaction processing performance.
摘要:
A method for duplicating transactions in a disaster recover system is disclosed. In this method, transactions and queries input to a primary database system are copied to a secondary database system and both database systems execute the queries and save the results permanently to each database, thereby maintaining duplicated data. When executing a query on the primary database system, if the query is a commit, the primary system simultaneously copies uncopied queries placed in a queue to the secondary database system and then executes the query. By using this processing procedure, the invention realizes a disaster recovery system which carries out copying transactions from one site to another site without losing the transactions, while reducing the influence of copy operation on the transaction processing performance.
摘要:
A high availability database system, subject to a failure causing data corruption in the active server system, may recover valid data prior to the corruption, and use the protected and recovered data to effect a failover. At the time when a stand-by computer system detects occurrence of a failure, a pair split is done to the data area to protect the data area data of time T0, just before the occurrence of the failure, and another pair split is done to the log area at the time, where the log area is corrupted or a time T3, where the failover is to take effect without corrupting data, to protect the log area containing data at a given time between time T0 and time T3. By using the data and log areas thus protected, the stand-by computer system may take over valid data and log areas to perform a failover.
摘要:
A method for duplicating transactions in a disaster recover system is disclosed. In this method, transactions and queries input to a primary database system are copied to a secondary database system and both database systems execute the queries and save the results permanently to each database, thereby maintaining duplicated data. When executing a query on the primary database system, if the query is a commit, the primary system simultaneously copies uncopied queries placed in a queue to the secondary database system and then executes the query. By using this processing procedure, the invention realizes a disaster recovery system which carries out copying transactions from one site to another site without losing the transactions, while reducing the influence of copy operation on the transaction processing performance.
摘要:
In a high available clustered computer system, a standby computer starts up takeover preparation procedures at a time when occurrence of a failure is watched in an active computer and failover procedures will be started up from the takeover preparation completion status when the failure is detected in the active computer. Thus, speeding up of failover preparation procedures is realized. With such arrangement, it is possible to realize failover procedures by the hot-standby procedures when a failure occurs in an active computer.
摘要:
In a high available clustered computer system, a standby computer starts up takeover preparation procedures at a time when occurrence of a failure is watched in an active computer and failover procedures will be started up from the takeover preparation completion status when the failure is detected in the active computer. Thus, speeding up of failover preparation procedures is realized.With such arrangement, it is possible to realize failover procedures by the hot-standby procedures when a failure occurs in an active computer.
摘要:
An application processing system including a database server and a storage device which is connected with a standby application processing system including a secondary database server and a secondary storage device to continue to carry out application processing in the case of a fault, disaster, etc. or for maintenance. The storage device of the application processing system issues a log disk update request to the secondary database server of the standby system to update a log disk of the standby system and thereby create a duplicate of the log disk for the DBMS of the application processing system. This allows the DBMS of the standby system to roll forward the log data in the duplicated log to update duplicated data on the secondary storage device.
摘要:
Provided is a method of changing the configuration of a shared-nothing database system without shutting down the system. The configuration changing method for a shared-nothing database system includes plural database servers, a storage which provides data areas to the database servers, and a management server which has a database management system and divides a transaction to allocate pieces of the transaction to the database servers, and the configuration changing method allows no two of the database servers to access the same data area. The configuration changing method changes the configurations of the database servers by specifying which data area is to be reallocated, judging whether or not the specified data area can be reallocated, and reallocating the specified data area without shutting down the database management system when it is judged that the specified data area can be reallocated.
摘要:
Provided is a failover method for a cluster system for realizing smooth failover of the guest OS's, even when there are many guest OS's, while reducing consumption of computer resources of a server. Smooth failover is realized by preventing competition during failover even when the number of guest OS's is increased. In a cluster configuration in which a slave/master cluster program is operated in a guest OS/host OS, the master cluster program (510) collects and transmits heartbeats of the slave cluster program, thereby realizing failure monitoring through the certain amount of heartbeats without depending on the number of guest OS's. Further, when the master cluster program monitors failures of the slave cluster program of its own computer to find a normal operation of the guest OS, the amount of communication through heartbeats is reduced by eliminating the necessity of communication to a standby system slave cluster program.