Patent ID: 7389380
Filing Date: 2008-06-17
Classification: G06F

Abstract:
1. A disk array device, comprising plural clusters, each of the plural clusters comprising a basic memory unit mounted with a basic memory and an expanded memory unit mounted with an expanded memory, and a maintenance control units, wherein control information of the disk array device includes management information and directory information, the management information includes device configuration information of the disk array device or information necessary for controlling operation of the disk array device, and the management information is duplicated in each of the clusters, the directory information includes storage structure information of a cache memory of the disk array device or control information for managing information related to the cache memory, and the directory information is different for each of the clusters, and the maintenance control unit is configured to store in the basic memory of each of the clusters identical management information; store in the expanded memory of each of the clusters respective directory information; detect whether or not a failure occurs in at least one of the basic memories and expanded memories, in response to detecting a failure, determine whether or not the failure has occurred in at least one of the basic memories, in response to determining that a failure has occurred in at least one of the basic memories, process maintenance blocking for a basic memory unit of which basic memory has the failure, replace the basic memory which has the failure with a normal basic memory, copy the management information to the normal basic memory from one of the memories in which failure has not occurred, in response to determining that a failure has not occurred in at least one of the basic memories but occurred in at least one of the expanded memories, start pseudo through operation, overwrite the directory information stored on the expanded memory into a basic memory associated with the expanded memory in which the failure has occurred so as to reestablish the directory information in the basic memory associated with the expanded memory in which the failure has occurred, stop pseudo through operation in response to completion of reestablishment of the directory information in the basic memory associated with the expanded memory in which the failure has occurred, process maintenance blocking for the expanded memory in which the failure has occurred, replace the expanded memory in which the failure has occurred with a normal expanded memory, overwrite the directory information on the normal expanded memory so as to reestablish the directory information therein; switch reference of the directory information from the basic memory associated with the expanded memory in which the failure has occurred to the normal expanded memory in response to completion of reestablishment of the directory information, delete the directory information in the basic memory associated with the expanded memory in which the failure has occurred, and copy the management information to the basic memory associated with the expanded memory in which the failure has occurred from a memory in which the failure has not occurred.