Patent ID: 7617255

Claim:
A storage system comprising a host computer including a retrieval request issuing section for issuing a retrieval request specifying at least a restoring target file and a retrieval condition including arbitrary keyword data irrelevant to a timestamp of said restoring target file thereby recovering said restoring target file as existing in a data volume at any arbitrary time point without causing a user to set a recovery time point before issuing the retrieval request; and a storage device including the data volume storing data written from the host computer, and a journal volume storing update histories of the data in the data volume, each of the update histories including update time information indicating an update time and update data written to the data volume, wherein if said retrieval request does not specify a time point or a time period when the restoring target file is created, updated or deleted, the storage device detects a first appearance time point and a last appearance time point of the restoring target file based upon the restoring target file and the retrieval condition including the arbitrary keyword data, and the storage device sets time points between the first and last appearance time points when the restoring target file is updated as respective candidate recovery time points in a recovery time point candidate list, said first appearance time point is a first time point when the recovery target file satisfies the retrieval condition, said last appearance time point is a last time point when the recovery target file satisfies the retrieval condition, wherein if said retrieval request specifies a time period but not a time point when the restoring target file is updated or deleted, the storage device narrows down respective candidate recovery time points in the recovery time point candidate list to be within said time period, wherein in order for a user to select one desired recovery time point from the respective candidate recovery time points, the storage device sends to the host computer the recovery time point candidate list including the respective candidate recovery time points to be displayed to the user, wherein the host computer sends to the storage device recovery time point information specifying said one desired recovery time point as selected by the user, and wherein the storage device restores at least one restoring target file corresponding to the selected recovery time point by using the update histories, when receiving the recovery time point information from the host computer.