Patent ID: 7698320
Filing Date: 2010-04-13
Classification: G06F

Abstract:
1. A storage system, which is coupled to a computer that implements a database management system having a managing unit for recording a log in a log file stored in the storage system in correspondence with identification information of a generated check point when a check point is generated, for recording the identification information of the generated check point in the control file, and for notifying such a fact that the check point has been generated to the storage system in combination with the identification information of the check point; a log analyzing unit for, in case of which the log analyzing unit receives a recovery instruction including a reconstruction time instant, retrieving a log corresponding to the reconstruction time instant included in the recovery instruction from the log file to acquire a log which has been recorded before a time instant when the retrieved log corresponding to the reconstruction time instant was recorded and includes identification information of the latest check point, and transmitting the identification information of the check point included in the acquired log to the storage system in combination with the restore instruction; and a log applying unit for applying the log corresponding to the identification information of the check point recorded in the control file restored by the storage system up to the log corresponding to the reconstruction time instant with respect to the database file restored by the storage system, the storage system comprising: a control unit for processing an access request transmitted from the computer; a first storage device for storing thereinto data; and a second storage device for storing thereinto a journal corresponding to an update history of the data stored in the first storage device, wherein: the control unit comprises: a cache memory for temporarily storing thereinto data and the journal which are transmitted and received between the storage system and the computer; a journal control unit operated for, in case of which the control unit receives an update instruction with respect to the data stored in the first storage device, setting the journal as a journal under overwrite status to newly generate a journal; a journal overwrite judging unit for, in case of which the control unit receives an update instruction with respect to the data stored in the first storage device, judging whether or not the journal corresponding to the same address generated by updating data at an address identical to the address where the data to be updated is stored has already been stored in the cache memory and is under overwritable status; and a journal lasting unit for, in case of which the control unit receives a predetermined instruction including predetermined identification information from the computer, which specifies a time instant when the data stored in the first storage device is restored, changing the journal under overwritable status stored in the cache memory into a journal under not-overwritable status; the control unit writes the data stored in the cache memory in order to reflect the data in one of the first storage device and the second storage device at predetermined timing; in case of which the journal control unit receives an update instruction with respect to the data stored in the first storage device and in case of which the journal corresponding to the same address has already been stored in the cache memory and is under overwritable status, the journal control unit overwrites the newly generated journal on the journal corresponding to the same address, and in case of which the journal corresponding to the same address is not stored in the cache memory, or in case of which the journal corresponding to the same address is under not-overwritable status, the journal control unit stores the newly generated journal into a new area of the cache memory; in case of which the journal control unit receives the predetermined instruction from the computer, the journal control unit generates a journal under not-overwritable status corresponding to predetermined identification information included in the predetermined instruction and stores the generated journal into the cache memory after the process operation executed by the journal lasting unit; and in case of which the journal control unit receives a restore instruction including the predetermined identification information from the computer, the journal control unit restores the data stored in the first storage device by employing a journal recorded in the second storage device before the journal corresponding to the predetermined identification information included in the received restore instruction.