摘要:
In a DR system, from the viewpoint of device cost, when search is not carried out, a physical application where log recovery is available by inexpensive DB appliance server is adopted. Further, a local mirror operation at a secondary site is not carried out. Furthermore, from the viewpoint of operation, by a log apply function unit, the tendencies of a log application and operations are monitored, and a search process is accepted according to the progress conditions of the log application. When the log application does not catch up sufficiently, the search is not accepted. Moreover, when a consistency guarantee of a secondary DB is made, not transactions in process at the moment of search instruction are undone (rolled back), but only transactions in process at the moment of a search instruction are redone (rolled forward).
摘要:
The invention provides an application technique of a backup data in which a backup data can be utilized by creating a backup data including no indeterminate data in a backup system. In a backup system including a primary system and a backup system, the method of creating the backup data includes: a data update record rerun step for rerunning a data update record to a backup data; and a backup data creation step for starting a read to a backup data B, stopping a read to a backup data A, copying the backup data to the backup data A, starting the read to the backup data A, stopping the read to the backup data B, and copying the backup data A to the backup data B.
摘要:
To generate backup data based on a log while a power consumption of a standby system is reduced, method for data backup is provided in which a first computer system transmits a data update record, a second storage system of a second computer system receives and then stores the data update record, and a second computer of the second computer system generates a copy of data contained in the first computer system based on the stored data update record. The method for data backup includes monitoring the data update record transmitted by the first computer system, and stopping, when a predetermined first condition is satisfied, the second computer; and starting, when a predetermined second condition is satisfied, the second computer, thereby generating the copy of the data contained in the first computer system based on the stored data update record.
摘要:
A method of managing data by a storage system having first and second volumes according to a command from a server computer, including receiving a data access command from the server computer; specifying a data area that is designated in the data access command and reading data in the data area from the first volume; judging whether the data access command contains a data evacuating instruction; judging whether the data in the data area has been evacuated to the second volume when the data read command contains the data evacuating instruction; evacuating the data in the data area to the second volume when the data in the data area has not been evacuated to the second volume; and sending the data in the data area to the server computer. The invention reduces loads on the storage system when a differential snapshot is used.
摘要:
A technology for verifying backup data capable of synchronizing timings of checksum calculation and verifying data consistency regardless of the storing position of the data is provided. In a backup system using a data update log, a checksum of data of a backup source and a checksum of backup data are checked, thereby verifying data consistency. Data check log generation means and the like are provided so that the data update log and the data check log are transmitted in order to a secondary site. By this means, the timings of the checksum calculation are synchronized. Further, by providing data area extraction means and the like, the verification of data consistency can be performed regardless of the storing position of the data.
摘要:
Provided is a backup method including a step (S1) of reading a log which is a data update difference, and identifying a data storage area (page) of backup data, a step (S2) of determining high/low reusability of the identified data storage area, a step (S3) of storing a log corresponding to a data storage area determined to be low in reusability in a log storage area preset on a memory, and a step (S4) of applying a log corresponding to a data storage area determined to be high in reusability to the identified data storage area in a cache area set on the memory, and updating the data storage area. Thus, by further reducing the number of I/O times in an external storage system of a standby system which backs up data by log transfer, it is possible to reduce introduction costs of a backup system and its normal-time operation's costs at normal times.
摘要:
A disaster recovery technology capable of achieving the high-speed FO and correctly reading the logs even if the unit of logs written in the main site is large is provided. In the disaster recovery system comprising a main site and a sub-site, when the writing in units of a log block consisting of a plurality of log records is performed in the main site and the logs are applied in the sub-site, the log blocks are read from the sub-storage to verify the consistency, and it is determined whether the reading process conflicts with the writing process through the remote copy operation when reading the logs. Then, only the log blocks in which the reading process does not conflict with the writing process as a result of the determination are applied to the database. Thereby, the logs are applied in the sub-site independently to recover the database.
摘要:
A technology capable of preventing a problem which occurs when log writing of a preceding transaction fails while reducing waiting time of a subsequent transaction is provided. A database control method for releasing locking of data held by a transaction upon reception of a transaction completion instruction from an operation terminal or the like by a database is provided. The database includes an exclusive control module, a log output module, and a log buffer. The log output module stores a transaction completion log in the log buffer upon reception of the transaction completion instruction from the operation terminal. The exclusive control module releases locking held by the transaction upon reception of storage of the transaction completion log in the log buffer.
摘要:
To reduce operational and management costs during normal operations while recovering a database without loss and maintaining on-line performance on a site. A first system includes a primary storage system (103) that stores a DB (107) and a main computer (100) that executes a primary DBMS (101), which provides a DB. A second system includes a secondary (113) that receives from the primary storage system (103) a copy of a log, which shows update differences of the DB (107), and stores a secondary DBMS (117), and a subset (500) that recovers the secondary DB (117) according to the log that is copied from the primary storage system (103). When a failure occurs in the first system, the first system is switched to the second system. A second computer (110) that executes a second DBMS (111) is added to the second system, and the secondary DB (117) that is recovered or is being recovered in the subset (500) is taken over to the second computer (110).
摘要:
A technology for verifying backup data capable of synchronizing timings of checksum calculation and verifying data consistency regardless of the storing position of the data is provided. In a backup system using a data update log, a checksum of data of a backup source and a checksum of backup data are checked, thereby verifying data consistency. Data check log generation means and the like are provided so that the data update log and the data check log are transmitted in order to a secondary site. By this means, the timings of the checksum calculation are synchronized. Further, by providing data area extraction means and the like, the verification of data consistency can be performed regardless of the storing position of the data.