CONTROLLER, FLASH MEMORY APPARATUS, METHOD FOR IDENTIFYING DATA BLOCK STABILITY, AND METHOD FOR STORING DATA IN FLASH MEMORY APPARATUS

• US 20160216915A1
• Filed: 03/30/2016
• Published: 07/28/2016
• Est. Priority Date: 12/05/2014
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: WU, Liming, HUANG, Bin, ZHAO, Wan
• Granted Patent: US 9,772,790 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 12/02 Addressing or allocation; Relocation program address sequencing G06F9/00; arrangements for selecting an address in a digital store G11C8/00
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2212/1036 Life time enhancement
• CPC Class Codes: G06F 2212/7205 Cleaning, compaction, garbage collection, erase control
• CPC Class Codes: G06F 3/0608 Saving storage space on storage systems
• CPC Class Codes: G06F 3/0616 in relation to life time, e.g. increasing Mean Time Between Failures [MTBF]
• CPC Class Codes: G06F 3/0641 De-duplication techniques
• CPC Class Codes: G06F 3/0679 Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]

Abstract

In a method for controlling data stored in an Solid State Disk (SSD) of a data de-duplication system, a storage controller obtains stability information of a data block. The stability information comprises a reference count of the data block and a length of a period of time when the data block is stored in the SSD. The storage controller identifies a stability level of the data block according to the stability information, and sends the stability level of the data block to the SSD. The SSD moves the data block to a target block which corresponds to the stability level. Thereby, the SSD can store data blocks having a same stability level together.

Claims

1. A method for controlling data stored in a Solid State Drive (SSD) memory in a storage system having a data de-duplication function, comprising:

obtaining, by a storage controller of the storage system, stability information of a data segment stored in the SSD, wherein the stability information comprises a reference count of the data segment and an age of the data segment, wherein the age of the data segment corresponds to a length of a period of time the data segment has been stored in the SSD, wherein the reference count of the data segment is equal to a number of times that the storage controller receives the data segment, and wherein the SSD includes one or more blocks;

identifying, by the storage controller, a stability level of the data segment based on the reference count and the age of the data segment, wherein the stability level corresponds to a probability of the data segment being changed; and

sending to the SSD, by the storage controller, a logical address of the data segment and the stability level of the data segment, wherein the data segment is assigned to a block of the SSD with data segments having similar stability levels; and

moving, by the SSD, the data segment stored at the logical address to the assigned block.

2. The method according to claim 1, wherein the stability level corresponds to a range of values of the reference count and a single value of the age.

3. The method of claim 1, wherein the stability level corresponds to a range of values of the age and a single value of the reference count.

4. The method of claim 1, wherein the stability level corresponds to a range of values of the age and a range of values of the reference count.

5. The method according to claim 1 further comprising:

receiving by the storage controller, a new data segment;

obtaining by the storage controller, a fingerprint of the new data segment by performing a hash of the new data segment;

sending to the SSD by the storage controller, the fingerprint;

comparing by the SSD, the fingerprint of the new data segment to previously stored fingerprints of previously stored data segments;

sending by the SSD, a response to the storage controller indicating that no match was found for the fingerprint of the new data segment; and

sending by the storage controller, the new data segment to the SSD for storage.

6. The method according to claim 5, wherein the reference count of the new data segment is equal to an initial value, the method further comprising:

storing by the storage controller, the initial value as the reference count of the new data segment.

7. A storage controller in a storage system having a data de-duplication function, comprising:

a memory configured to store stability information of a data segment, wherein the data segment is stored in a Solid State Disk (SSD) of the storage system, that is in communication with the storage controller, wherein the stability information comprises a reference count of the data segment and an age of the data segment, wherein the age of the data segment corresponds to a length of a period of time the data segment has been stored in the SSD, and wherein the reference count of the data segment is the number of times that the storage controller receives the data segment; and

a processor configured to;

obtain a stability level of the data segment based on the reference count of the data segment and the age of the data segment, wherein the stability level corresponds to a chance of the data segment being changed; and

send a logical address of the data segment and the stability level of the data segment to the SSD.

8. The storage controller of claim 7, wherein the stability level corresponds to a range of values of the reference count and a single value of the age.

9. The storage controller of claim 7, wherein the stability level corresponds to a range of values of the age and a single value of the reference count.

10. The storage controller of claim 7, wherein the stability level corresponds to a range of values of the age and a range of values of the reference count.

11. The storage controller according to claim 7,

wherein the processor is further configured to:

receive a new data segment;

obtain a fingerprint of the new data segment by performing a hash of the new data segment, wherein the SSD stores a fingerprint corresponding to each data segment stored;

send the fingerprint of the new data segment to the SSD;

receive a confirmation from the SSD, that no fingerprint stored in the SSD matches the fingerprint of the new data segment; and

send the new data segment to the SSD for storage.

12. The storage controller according to claim 11, wherein the reference count of the new data segment is equal to an initial value,

wherein the processor is further configured to store the initial value as the reference count of the new data segment.

13. A Solid State Drive (SSD) in a storage system having a data de-duplication function, comprising a flash memory chip and a SSD controller,

wherein the flash memory chip includes a plurality of blocks, wherein each block stores data segments with similar stability level;

and

wherein a SSD controller is configured to;

obtain a logical address of a data segment;

receive a stability level of the data segment from a storage controller in communication with the SSD, wherein the stability level corresponds to a probability of the data segment being changed;

assign a block of the plurality of blocks for the data segment, wherein the assigned block stores data segments with stability levels similar to the stability level of the data segment; and

move the data segment stored at the logical address to the assigned block.

14. The SSD according to claim 13, wherein the data segment was stored in a source block of the plurality of blocks before being moved to the assigned block, and wherein the source block includes a largest amount of invalid data.

15. The SSD according to claim 13, wherein the data segment was stored in a source block that has not been erased for a longest time compared to other blocks in the SSD.