Patent ID: 7925633
Filing Date: 2011-04-12
Classification: G06F

Abstract:
1. A data recovery and takeover method in a disaster recovery system including a primary site having a first storage system storing a first database and a first server provided with a first database management system (DBMS) managing the first database, and a secondary site, located remotely from the primary site, having a second storage system storing a second database which duplicates the first database and a recovery module, the method comprising: copying a log indicating an update difference in said first database into a log file formed in the second storage system by a remote copy via an inter storage network which connects the first storage system and the second storage system, when the update difference is generated in said first database; when the log indicating the update difference is copied by the remote copy, reading out the copy of the log from the log file formed in the second storage system by the recovery module and applying the log on said second database by the recovery module, in a log applying process which is kept alive until the second site receives a failover instruction; upon a time when the second site receives the failover instruction, interrupting the log applying operation of the data recovery process and marking a log record indicating a start of an oldest uncommitted transaction at that time as a check point; according to the failover instruction, starting in the secondary site a second server which is provided with a second DBMS which is to take over the first DBMS; informing the second server of execution condition of the interrupted data recovery process including information of the check point from the recovery module, taking over by the second DBMS provided in the second server a data recovery of the second database.