Database recovery method applying update journal and database log

A computer system, comprising:

• a computer having a database management system;
• and
• a storage system for storing data accessed from the computer, wherein:
• the computer comprises a port connected to the storage system, a processor connected to the port and a memory connected to the processor;
• the storage system comprises a port connected to the computer, a control unit connected to the port and including a processor and a memory and a disk drive for storing data which is a target of a write request issued by the computer;
• the disk drive includes a data volume for storing the data, a snapshot volume corresponding to a copy of the data volume, a database log for storing an update log of the data and an update journal for storing update information of the data volume;
• and
• the database management system
• records a recovery point for indicating an end point of a range to which the update journal is to be applied and a starting point of a range to which the database log is to be applied when the data volume is damaged during a normal operation of the computer system,
• applies the update journal to the snapshot volume up to the recovery point when an error occurs in the data volume,
• switches the updated snapshot volume to the data volume, and
• applies the database log after the recovery point to the data volume that is set by switching.