STORAGE CONTROL APPARATUS AND STORAGE CONTROL METHOD

• US 20130311707A1
• Filed: 05/16/2012
• Published: 11/21/2013
• Est. Priority Date: 05/16/2012
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Kawamura, Atsushi, Ogawa, Junji
• Granted Patent: US 9,183,136 B2
• Time in Patent Office: Days
• US Class Current: 711/103
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory

Abstract

A storage control apparatus comprises a storage unit, an association unit, and an execution unit. The storage unit stores association information showing multiple physical chunks which are configured in a physical address space of a nonvolatile semiconductor memory, multiple logical storage areas which are configured in a logical address space of the nonvolatile semiconductor memory, multiple logical chunks which are respectively associated with the multiple physical chunks, and an association between a logical storage area and a logical chunk. The association unit changes the association by changing the association information in accordance with a state of the nonvolatile semiconductor memory, and identifies based on the association information a physical storage area corresponding to a logical storage area specified in an input/output request from a computer. The execution unit executes the input/output request with respect to the identified physical storage area.

Claims

1. A storage control apparatus, comprising:

a storage unit that stores association information showing multiple physical chunks which are configured in a physical address space of a nonvolatile semiconductor memory, multiple logical storage areas which are configured in a logical address space of the nonvolatile semiconductor memory, multiple logical chunks which are respectively associated with the multiple physical chunks, and an association between a logical storage area and a logical chunk;

an association unit which changes the association by changing the association information in accordance with states of the multiple physical chunks, and identifies based on the association information a physical storage area corresponding to a logical storage area specified by an input/output request; and

an execution unit which executes the input/output request with respect to the identified physical storage area.

2. The storage control apparatus according to claim 1, wherein the association information shows an association of a first physical chunk and a first logical chunk, an association of a second physical chunk and a second logical chunk, and an association of a first logical chunk and a first logical storage area, and

the association unit migrates data corresponding to the first logical storage area in the first physical chunk to the second physical chunk in accordance with the states of the multiple physical chunks, and

associates the first logical storage area with the second logical chunk in the association information.

3. The storage control apparatus according to claim 2, wherein the association information shows multiple physical blocks in each physical chunk and multiple physical pages in each physical block, multiple logical page groups configured in a logical address space, multiple logical pages in each logical page group, multiple logical slot groups in each logical chunk, and multiple logical slots in each logical slot group, and shows a first logical page in a first logical page group, a first slot group in the first logical chunk, and an association of the first logical slot group and the first logical page group, and

the association unit migrates data corresponding to the first logical page group in the first physical chunk to the second physical chunk in accordance with the states of the multiple physical chunks, and associates the first logical page group with a logical slot group in the second logical chunk.

4. The storage control apparatus according to claim 3, wherein the association unit measures a load of each logical page group, and based on results of the measurements, migrates data corresponding to the first logical page group in the first physical chunk to the second physical chunk, and associates the first logical page group with a logical slot group in the second logical chunk.

5. The storage control apparatus according to claim 4, wherein the load is a write frequency.

6. The storage control apparatus according to claim 5, wherein the association information shows a range of write frequencies of a logical page group associated with each logical chunk.

7. The storage control apparatus according to claim 6, wherein the association information shows the number of logical slot groups in each logical chunk.

8. The storage control apparatus according to claim 7, wherein, in a case where the number of logical slot groups in the second logical chunk is lower than a preconfigured criterion for the number of logical slot groups and the write frequency of the first logical page group is higher than a preconfigured criterion for the write frequency, the association unit associates the first logical page group with a logical slot group in the second logical chunk.

9. The storage control apparatus according to claim 8, wherein the execution unit writes data in free physical page units, and erases data in physical block units.

10. The storage control apparatus according to claim 9, wherein the non-volatile semiconductor memory is a flash memory.

11. The storage control apparatus according to claim 3, wherein the storage unit comprises a queue for storing input/output requests in a sequence of execution by the execution unit,

the association information shows a logical chunk priority hich is the priority of each logical chunk, and

in a case where a second input/output request is received subsequent to a first input/output request, and, in addition, a logical chunk priority of a logical chunk associated with a target of the second input/output request is higher than a logical chunk priority of a logical chunk associated with a target of the first input/output request, the association unit arranges the second input/output request ahead of the first input/output request in the execution sequence of the queue.

12. The storage control apparatus according to claim 11, wherein the association information shows a logical page group priority which is the priority of each logical page group, shows that a logical page group priority of a specific logical page group is higher than a preconfigured criterion for a logical page group priority, and shows that a logical chunk priority of a specific logical chunk is higher than a preconfigured criterion of the logical chunk, and

the association unit associates the specified logical page group with a logical slot group in the specific logical chunk.

13. A storage control method, comprising:

storing association information showing multiple physical chunks which are configured in a physical address space of a nonvolatile semiconductor memory, multiple physical storage areas in each multiple chunk, multiple logical chunks which are respectively associated with the multiple physical chunks, multiple logical storage areas configured in a logical address space of the nonvolatile semiconductor memory, and an association between a logical storage area and a logical chunk;

changing the association by changing the association information in accordance with a state of the nonvolatile semiconductor memory;

identifying based on the association information a physical storage area corresponding to a logical storage area specified in accordance with an input/output request from a computer; and

executing an input/output request from the computer with respect to the identified physical storage area,

wherein the association information shows an association of a first physical chunk and a first logical chunk, an association of a second physical chunk and a second logical chunk, and an association of a first logical chunk and a first logical storage area, and

the change associates the first logical storage area with the second logical chunk in the association information in accordance with a state of the nonvolatile semiconductor memory.