Method of restoring data by CDP utilizing file system information

A disk device connected to a NAS device which receives, from a host computer, a request to read data from a file and a request to write data in a file, comprising:

• at least one interface connected to the NAS device;
• at least one processor connected to the interface;
• at least one memory connected to the processor;
• and
• at least one disk drive which stores data requested by the host computer to be written,
• wherein the processor reads and writes data from and to blocks of the disk drive,
• wherein the processor provides, to the NAS device, storage areas of the disk drive as plural volumes including a first volume, a second volume, and a third volume, the first volume storing a file which is accessed by the host computer, the second volume storing a block write history which includes association between each of the blocks and a time when data is written in the block, the third volume storing a replication of data existing in the first volume at a specific time,
• wherein the processor refers to the block write history stored in the second volume to overwrite the replication data stored in the third volume with a replication of data existing in the first volume at a different time from the specific time,
• wherein the block write history stored in the second volume further includes information about which block is associated with which file,
• wherein, upon receiving file designation from the NAS device, the processor extracts from the block write history stored in the second volume only a part of the block write history relevant to blocks that are associated with the designated file, and
• wherein the processor sends the extracted part of the block write history to the NAS device.

A method of restoring data in a storage system which is connected to a host computer and which has at least one disk drive in which data requested by the host computer to be written is stored, comprising the steps of:

• receiving from the host computer a request to read data from a file and a request to write data in a file;
• reading and writing data from and to blocks in the disk drive as requested by the received read request and write request;
• providing storage areas of the disk drive as plural volumes including a first volume, a second volume, and a third volume, the first volume storing a file which is accessed by the host computer, the second volume storing a block write history which includes association between each of the blocks, a time and information about which block is associated with which file when data is written in the block, the third volume storing a replication of data existing in the first volume at a specific time;
• referring to the block write history stored in the second volume to overwrite the replication data stored in the third volume with a replication of data existing in the first volume at a different time from the specific time;
• upon receiving file designation, extracting from the block write history stored in the second volume a part of the block write history relevant to blocks that are associated with the designated file;
• and
• sending the extracted part of the block write history.

A storage system connected to a host computer, comprising:

• at least one interface connected to the host computer;
• at least one processor connected to the interface;
• at least one memory connected to the processor;
• and
• at least one disk drive which stores data requested by the host computer to be written,
• wherein the processor executes programs stored in the memory to implement a file system input/output processing unit receiving from the host computer a request to read data from a file and a request to write data in a file, and a block input/output processing unit reading and writing data from and to blocks in the disk drive,
• wherein the block input/output processing unit provides, to the file system input/output processing unit, storage areas of the disk drive as plural volumes including a first volume, a second volume, and a third volume, the first volume storing a file which is accessed by the host computer, the second volume storing a block write history which includes association between each of the blocks and a time when data is written in the block, the third volume storing a replication of data existing in the first volume at a specific time,
• wherein the block input/output processing unit refers to the block write history stored in the second volume to overwrite the replication data stored in the third volume with a replication of data existing in the first volume at a different time from the specific time,
• wherein the block input/output processing unit extracts, when block designation is received from the file system input/output processing unit, a part of the block write history relevant to the designated blocks from the block write history stored in the second volume, and
• wherein the block input/output processing unit sends the extracted part of the block write history to the file system input/output processing unit.