Disaster recovery processing method and apparatus and storage unit for the same

A storage unit for performing processing by which contents of database processing carried out on a computer are forced to a database in said storage unit, comprising:

• a control processing portion for receiving an access request transmitted from said computer, and judging whether said received access request is a write request or a read request;
• and
• an update processing portion for judging whether contents to be written are log information of a plurality of log records indicating contents of database processing carried out on said computer when said received access request is a write request and converting position information indicated in said log information, with reference to a conversion table indicating correspondence of logical position information recognized in said database processing on said computer, to physical position information in said storage unit when said contents to be written are said log information,
• wherein, when said received access request is a write request and said contents to be written are log information, said update processing portion chains said plurality of log records for each transaction to have a plurality of log record chains held in a log management table, deletes, when a COMMIT log is found in log information of said log records, information of a transaction of a log record chain including said COMMIT log from said plurality of log record chains, and updates data in a Logical Unit (LU) in said database area at physical position information in accordance with contents of said log information.

A database processing system for performing processing by which contents of database processing carried out on a computer are forced to a database in a storage unit, comprising:

• a computer, including a database management processing portion, for transmitting a write request of log information from said computer to a storage unit when there occurs necessity to reflect contents of a database buffer of said computer onto a storage in said storage unit, said log information of a plurality of log records indicating contents of database processing carried out on said database buffer and transmitting a read request of data to be accessed in said database processing from said computer to said storage unit when said data is absent from said database buffer;
• a control processing portion of said storage unit for receiving an access request transmitted from said computer, and judging whether said received access request is a write request or a read request;
• and
• an update processing portion of said storage unit for judging whether contents to be written are said log information indicating contents of database processing carried out on said computer when said received access request is a write request, converting position information indicated in said log information, with reference to a conversion table indicating correspondence of logical position information recognized in said database processing on said computer, to physical position information in said storage unit when said contents to be written are said log information,
• wherein, when said received access request is a write request and said contents to be written are log information, said update processing portion chains said plurality of log records for each transaction to have a plurality of log record chains held in a log management table, deletes, when a COMMIT lop is found in lop information of said lop records, information of a transaction of a lop record chain including said COMMIT lop from said plurality of log record chains, and updates data in a Logical Unit (LU) in said database area at physical position information in accordance with contents of said log information.

A database processing program having computer readable codes stored on a storage medium, for making a computer function as a storage unit for performing processing when read into a computer by which contents of database processing carried out on said computer are forced to a database in a storage unit connected through a network to said computer, wherein said database processing program makes said computer function as:

• a control processing portion for receiving an access request transmitted from said computer, and judging whether said received access request is a write request or a read request;
• and
• an update processing portion for judging whether contents to be written are log information of a plurality of log records indicating said contents of said database processing carried out on said computer when said received access request is a write request and converting position information indicated in said log information, with reference to a conversion table indicating correspondence of logical position information recognized in said database processing on said computer, to physical position information in said storage unit when said contents to be written are said log information,
• wherein, when said received access request is a write request and said contents to be written are log information, said update processing portion further chains said plurality of log records for each transaction to have a plurality of log record chains held in a log management table, deletes, when a COMMIT log is found in log information of said log records, information of a transaction of a log record chain including said COMMIT log from said plurality of log record chains, and updates data in a Logical Unit (LU) in said database area at physical position information in accordance with contents of said log information.