STORAGE DEVICE, APPARATUS HAVING STORAGE DEVICE, AND STORAGE CONTROL METHOD

• US 20160328154A1
• Filed: 02/26/2014
• Published: 11/10/2016
• Est. Priority Date: 02/26/2014
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: MIZUSHIMA, Nagamasa, OGAWA, Junji, KAWAMURA, Atsushi
• Granted Patent: US 10,444,992 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2212/401 Compressed data
• CPC Class Codes: G06F 3/0604 Improving or facilitating administration, e.g. storage management
• CPC Class Codes: G06F 3/0616 in relation to life time, e.g. increasing Mean Time Between Failures [MTBF]
• CPC Class Codes: G06F 3/0644 Management of space entities, e.g. partitions, extents, pools
• CPC Class Codes: G06F 3/0665 at area level, e.g. provisioning of virtual or logical volumes
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]
• CPC Class Codes: G06F 3/0679 Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]
• CPC Class Codes: G11C 7/1006 Data managing, e.g. manipulating data before writing or reading out, data bus switches or control circuits therefor

Abstract

A storage device provides a logical space based on a storage medium that is configured by a plurality of logical areas to the higher-level apparatus, and a base data range exists in the storage medium for each logical area. The storage device reads the base data from the base data range that is corresponded to a write destination logical area to which the write destination logical address belongs, and creates difference data that is an exclusive OR of first data that is the base data and second data that is any one of data based on write data and the write data. The storage device creates compressed difference data by compressing the difference data, writes the compressed difference data to the storage medium, and associates a difference data range that is a range in which the compressed difference data has been written with the write destination logical area.

Claims

1. A storage device coupled to a higher-level apparatus, comprising:

a storage medium; and

a medium controller configured to control an I/O (Input/Output) to the storage medium and to provide a logical space based on the storage medium to the higher-level apparatus,

the logical space being configured by a plurality of logical areas,

a base data range existing in the storage medium for each logical area, and

the medium controller being configured to

receive a write command that specifies a write destination logical address from the higher-level apparatus,

read the base data from the base data range that is corresponded to a write destination logical area to which the write destination logical address belongs,

create difference data that is an exclusive OR of first data that is the base data and second data that is any one of data based on write data that conforms to the write command and the write data,

create compressed difference data by compressing the difference data,

write the compressed difference data to the storage medium, and

associate a difference data range that is a range in which the compressed difference data has been written with the write destination logical area.

2. The storage device according to claim 1, wherein

the medium controller is configured to

create compressed second data by compressing the second data or data based on the second data, and

if third data that includes the compressed difference data is smaller than the compressed second data, write the compressed difference data that includes the third data to the storage medium, and

the third data is the compressed difference data or data that is configured by the compressed difference data and a code part that is one or more guarantee codes in the first data.

3. The storage device according to claim 2, wherein

the medium controller is configured to write not the third data but the compressed second data to the storage medium if the compressed second data is smaller than the third data, and

the medium controller is configured to update the base data range of the write destination logical area from the base data range that is associated with the write destination logical area to a compressed second data range that is a range in which the compressed second data has been written, in the case where the medium controller writes the compressed second data to the storage medium.

4. The storage device according to claim 3, wherein the medium controller is configured to write not the third data but the compressed second data to the storage medium, in the case where a size of the compressed second data is equivalent to that of the third data.

5. The storage device according to claim 2, wherein the medium controller is configured to update the difference data range of the write destination logical area from the difference data range that is associated with the write destination logical area to a third data range that is a range in which the third data has been written, in the case where the medium controller writes the third data to the storage medium and the difference data range has been associated with the write destination logical area.

6. The storage device according to claim 1, wherein

the storage medium is configured by a plurality of physical areas, in which the input and output of data are executed on a physical area basis,

the first data is the base data on a physical area basis,

the second data is the write data on a physical area basis, and

the difference data is an exclusive OR of the base data on a physical area basis and the write data of a physical area size.

7. The storage device according to claim 1, wherein

the storage medium is configured by a plurality of physical areas, in which the input and output of data are executed on a physical area basis,

the first data is the base data on a physical area basis,

the second data is post-update data on a physical area basis,

the post-update data on a physical area basis is

data that is created based on the base data on a physical area basis and the write data less than a physical area unit, or

data that is created based on post-update data on a physical area basis that is created by an exclusive OR of the base data on a physical area basis and the difference data that is associated with the write destination logical area and the write data less than a physical area unit, and

the difference data is an exclusive OR of the base data on a physical area basis and the post-update data on a physical area basis.

8. The storage device according to claim 1, wherein

the storage medium is configured by a plurality of physical areas, in which the input and output of data are executed on a physical area basis,

two or more logical areas that include the write destination logical area are associated with the same base data range,

the first data is a base sector data part that is a data part other than one or more guarantee codes of data on a physical area basis,

the second data is a write sector data part that is a data part other than one or more guarantee codes of the write data on a physical area basis,

the difference data is an exclusive OR of the base sector data part and the write sector data part, and

the medium controller is configured to write the third data that is configured by the compressed difference data and a code part that is one or more guarantee codes of the write data on a physical area basis to the storage medium.

9. The storage device according to claim 8, wherein

the medium controller is configured to

create compressed write data by compressing the write data,

if the third data is smaller than the compressed write data, write the third data to the storage medium, and

if the compressed write data is smaller than the third data, write not the third data but the compressed write data to the storage medium.

10. The storage device according to claim 1, wherein

the storage medium is configured by a plurality of physical areas, in which the input and output of data are executed on a physical area basis,

two or more logical areas that include the write destination logical area are associated with the same base data range,

the first data is a base sector data part that is a data part other than one or more guarantee codes of data on a physical area basis,

the second data is post-update data on a physical area basis,

the post-update data on a physical area basis is

data that is configured by the base sector data part and a stored code part that is one or more guarantee codes associated with the write destination logical area and stored in the storage medium, or

data that is created based on provisional data on a physical area basis and the write data less than a physical area unit,

the provisional data on a physical area basis is data that is configured by pre-update data that is created by an exclusive OR of the base sector data part and the difference data that is associated with the write destination logical area and the stored code part,

the difference data is an exclusive OR of the post-update sector data part that is data part other than one or more guarantee codes of the post-update data on a physical area basis and the base data part, and

the medium controller is configured to write the third data that is configured by the compressed difference data and a code part that is one or more guarantee codes of the post-update data on a physical area basis to the storage medium.

11. The storage device according to claim 10, wherein

the medium controller is configured to

create compressed post-update data by compressing the post-update data on a physical area basis;

if the third data is smaller than the compressed post-update data, write the third data to the storage medium; and

if the compressed post-update data is smaller than the third data, write not the third data but the compressed post-update data to the storage medium.

12. The storage device according to claim 2, wherein the medium controller is configured to write the third data to the storage medium, if the number of predetermined values is equivalent to or larger than a predetermined number for the difference data.

13. The storage device according to claim 2, wherein the medium controller is configured to write the compressed second data to the storage medium, if all of the difference data is data that is configured by predetermined values or the write data is data of a predetermined pattern.

14. An apparatus comprising:

a storage device; and

a processor configured to control an I/O to the storage device,

the storage device including a storage medium and a medium controller that is configured to control an I/O to the storage medium and to provide a logical space based on the storage medium to the processor,

the logical space being configured by a plurality of logical areas,

a base data range exists in the storage medium for each logical area, and

the medium controller being configured to

receive a write command that specifies a write destination logical address from the processor,

read the base data from the base data range that is corresponded to a write destination logical area to which the write destination logical address belongs,

create difference data that is an exclusive OR of first data that is the base data and second data that is any one of data based on write data that conforms to the write command and the write data,

create compressed difference data by compressing the difference data,

write the compressed difference data to the storage medium, and

associate a difference data range that is a range in which the compressed difference data has been written with the write destination logical area.

15. A storage control method comprising:

providing a logical space that is a space based on the storage medium and that is configured by a plurality of logical areas to an higher-level apparatus;

receiving a write command that specifies a write destination logical address from the higher-level apparatus;

reading the base data from the base data range that is corresponded to a write destination logical area to which the write destination logical address belongs among a plurality of base data ranges that are associated with the plurality of logical areas,

creating difference data that is an exclusive OR of first data that is the base data and second data that is any one of data based on write data that conforms to the write command and the write data;

creating compressed difference data by compressing the difference data;

writing the compressed difference data to the storage medium; and

associating a difference data range that is a range in which the compressed difference data has been written with the write destination logical area.