Storage apparatus and method of managing data storage area

A method of managing a data storage area in a storage apparatus,

• wherein the storage apparatus includes a semiconductor storage media that has a plurality of storage devices, and a controller that is coupled to the semiconductor storage media,
• each of the storage devices has an upper limit of an erase count of data stored therein,
• the plurality of storage devices include a first storage device and a second storage device having an upper limit smaller than that of the first storage device,
• the controller includes an interface, a processor that is coupled to the interface, and a memory that is coupled to the processor,
• the memory stores storage media management information that is used to manage the semiconductor storage media,
• the storage media management information includes area conversion information including the correspondence of a first address to be specified as a storage destination of data and a second address of an area where data is stored, and a rewrite frequency of stored data is recorded for each area, and
• the method comprising:
• causing the controller to select an area corresponding to the first address;
• causing the controller to acquire the rewrite frequency of the selected area from the storage media management information;
• causing the controller to determine whether the acquired rewrite frequency is equal to or larger than a first threshold value;
• when the acquired rewrite frequency is equal to or larger than the first threshold value, causing the controller to select a first area to be provided by the first storage device;
• when the acquired rewrite frequency is smaller than the first threshold value, causing the controller to select a second area to be provided by the second storage device;
• and
• causing the controller to set a second address of the selected first area or second area to the second address corresponding to the first address, to thereby update the area conversion information.

A storage apparatus comprising:

• a flash memory module that has a plurality of flash memory chips;
• and
• a controller that is coupled to the flash memory module,
• wherein each of the flash memory chips has an upper limit of an erase count of data stored therein,
• the plurality of flash memory chips include a first flash memory chip and a second flash memory chip having an upper limit smaller than that of the first flash memory chip,
• the flash memory chips are managed in a block unit of a predetermined size,
• the controller includes an interface, a processor that is coupled to the interface, and a memory that is coupled to the processor,
• the memory stores block management information which is use to manage the blocks,
• the block management information includes block conversion information including correspondence of a logical address to be specified as a data storage destination and a physical address which is a physical address of a block, in which data is stored, and a substitute block list which is data rewritable and has a list of blocks not corresponding to the logical address,
• a rewrite frequency which is an erase count of data in each block for a predetermined period, and an erase count of data stored in the corresponding block are recorded, and
• when a data write request with respect to the flash memory module is received, the controller specifies the physical address corresponding to the logical address in the data write request on the basis of the block conversion information, to thereby specify a block in which requested data is written, acquires a rewrite frequency of the specified block from the storage media management information, determines whether or not the acquired rewrite frequency is equal to or larger than a first threshold value, when the acquired rewrite frequency is equal to or larger than the first threshold value, selects a first block in the first flash memory chip from the substitute block list and writes requested data in the selected first block, when the acquired rewrite frequency is smaller than the first threshold value, selects a second block in the second flash memory chip from the substitute block list and writes requested data in the selected second block, and after requested data is written, sets the physical address of the block, in which requested data is written, to the physical address corresponding to the logical address in the data write request, to thereby update the block conversion information.