Locally generating and storing RAID stripe parity with single relative memory address for storing data segments and parity in multiple non-volatile memory portions

• US 9,652,175 B2
• Filed: 06/02/2015
• Issued: 05/16/2017
• Est. Priority Date: 04/09/2015
• Status: Active Grant

• Current Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Original Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Inventors: Olbrich, Aaron K., Vanaraj, Anantharaj Thalaimalai, Viswasarai, Sainath
• Primary Examiner(s): KIM, HONG CHONG
• Application Number:
  US14/728,988
• Publication Number:
  US 20160299699A1
• Time in Patent Office: 714 Days
• Field of Search: 711114, 714 622, 710 21
• CPC Class Codes: G06F 11/1068 in sector programmable memories, e.g. flash disk G06F11/1072 takes precedence
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems
• CPC Class Codes: G06F 11/108 Parity data distribution in semiconductor storages, e.g. in SSD
• CPC Class Codes: G06F 3/0604 Improving or facilitating administration, e.g. storage management
• CPC Class Codes: G06F 3/0611 in relation to response time
• CPC Class Codes: G06F 3/0616 in relation to life time, e.g. increasing Mean Time Between Failures [MTBF]
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/0631 by allocating resources to storage systems
• CPC Class Codes: G06F 3/0638 Organizing or formatting or addressing of data
• CPC Class Codes: G06F 3/065 Replication mechanisms
• CPC Class Codes: G06F 3/0656 Data buffering arrangements
• CPC Class Codes: G06F 3/0659 Command handling arrangements, e.g. command buffers, queues, command scheduling
• CPC Class Codes: G06F 3/0679 Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]
• CPC Class Codes: G06F 3/0688 Non-volatile semiconductor memory arrays

Abstract

A memory controller receives a command to perform a memory operation, the command including a data packet comprising a plurality of data divisions. In response to receiving the command, for each individual memory device, the memory controller assigns to the individual memory device a respective data division, the respective data division including a plurality of data segments, and determines a single relative memory address associated with an address specified by the received command. The memory controller assembles a sub-request comprising a single contiguous instruction portion, which includes the single relative memory address and one or more instructions to perform the memory operation, and the respective data division, the respective data division following the single contiguous instruction portion, and transmits the sub-request to every memory portion of the number of memory portions of the individual memory device.

Claims

1. A method of performing memory operations in a storage system, the storage system having one or more memory controllers and a set of memory devices, each memory device comprising a plurality of memory portions, the method comprising:

at a memory controller;

in response to receiving a host command to write data, wherein the host command includes a data packet comprising one or more data divisions and a backup request to backup at least a portion of the data packet;

assigning a first data division of the data packet to a first memory device having M memory portions, wherein M is an integer greater than one, and the first data division includes a sequence of N data segments, wherein N is an integer less than or equal to M;

determining a single relative memory address associated with an address specified by the host command;

assembling a sub-request comprising the single relative memory address, the N data segments of the first data division, and a set of instructions, the set of instructions including instructions;

to write the N data segments in N memory portions of the first memory device, to perform an XOR operation on one or more of the N data segments, and to write a resulting XOR value in a particular memory portion of the M memory portions of the first memory device; and

transmitting the sub-request to every memory portion of the M memory portions of the first memory device.

2. The method of claim 1, wherein the set of instructions in the sub-request includes information to perform an XOR operation at a first memory portion of the M memory portions using at least one data segment in the sub-request and a predefined seed value stored in the first memory portion.

3. The method of claim 2, wherein the predefined seed value stored in the first memory portion is derived from the at least one data segment.

4. The method of claim 2, wherein the predefined seed value stored in the first memory portion is derived from the single relative memory address.

5. The method of claim 1, wherein the set of instructions includes an instruction for the particular memory portion of the M memory portions to generate an XOR of all N data segments and to store the resulting XOR value in the particular memory portion.

6. The method of claim 1, wherein the one or more XOR instructions includes an instruction for each memory portion of two or more of the M memory portions to generate an XOR of a particular pair of the N data segments and to store the resulting XOR value in the particular memory portion.

7. The method of claim 1, wherein the number of data segments, N, is equal to the number of memory portions, M, and the one or more XOR instructions includes an instruction for the particular memory portion to generate an XOR of a data segment corresponding to the particular memory portion, and to store the resulting XOR value in the particular memory portion.

8. The method of claim 1, wherein each data segment has a size equal to a non-integer multiple of the size of a page of data, and the sub-request further comprises memory portion markers positioned among the data segments.

9. A storage system, comprising:

a storage device that includes a set of memory devices, each memory device comprising a plurality of memory portions; and

a memory controller, having one or more processors and memory storing one or more programs to be executed by the one or more processors, configured to control operation of the storage system by;

responding to receiving a host command to write data, wherein the host command includes a data packet comprising one or more data divisions and a backup request to backup at least a portion of the data packet, by;

assigning a first data division of the data packet to a first memory device having M memory portions, wherein M is an integer greater than one, and the first data division includes a sequence of N data segments, wherein N is an integer less than or equal to M;

determining a single relative memory address associated with an address specified by the host command;

assembling a sub-request comprising the single relative memory address, the N data segments of the first data division, and a set of instructions, the set of instructions including instructions;

to write the N data segments in N memory portions of the first memory device, to perform an XOR operation on one or more of the N data segments, and to write a resulting XOR value in a particular memory portion of the M memory portions of the first memory device; and

transmitting the sub-request to every memory portion of the M memory portions of the first memory device.

10. The storage system of claim 9, wherein the memory controller includes a sub-request formation module for assembling the sub-request and a location determination module for determining the single relative memory address.

11. The storage system of claim 9, wherein the set of instructions in the sub-request includes information to perform an XOR operation at a first memory portion of the M memory portions using at least one data segment in the sub-request and a predefined seed value stored in the first memory portion.

12. The storage system of claim 10, wherein the predefined seed value stored in the first memory portion is derived from the at least one data segment.

13. The storage system of claim 10, wherein the predefined seed value stored in the first memory portion is derived from the single relative memory address.

14. The storage system of claim 9, wherein the set of instructions includes an instruction for the particular memory portion of the M memory portions to generate an XOR of all N data segments and to store the resulting XOR value in the particular memory portion.

15. The storage system of claim 9, wherein the one or more XOR instructions includes an instruction for each memory portion of two or more of the M memory portions to generate an XOR of a particular pair of the N data segments and to store the resulting XOR value in the particular memory portion.

16. The storage system of claim 9, wherein the number of data segments, N, is equal to the number of memory portions, M, and the one or more XOR instructions includes an instruction for the particular memory portion to generate an XOR of a data segment corresponding to the particular memory portion, and to store the resulting XOR value in the particular memory portion.

17. The storage system of claim 9, wherein each data segment has a size equal to a non-integer multiple of the size of a page of data, and the sub-request further comprises memory portion markers positioned among the data segments.

18. A non-transitory computer readable storage medium storing one or more programs, the one or more programs comprising instructions, which, when executed by a memory controller with one or more processors, cause the memory controller to:

receive a host command to write data, wherein the host command includes a data packet comprising one or more data divisions and a backup request to backup at least a portion of the data packet;

in response to receiving the host command;

assign a first data division of the data packet to a first memory device having M memory portions, wherein M is an integer greater than one, and the first data division includes a sequence of N data segments, wherein N is an integer less than or equal to M;

determine a single relative memory address associated with an address specified by the host command;

assemble a sub-request comprising the single relative memory address, the N data segments of the first data division, and a set of instructions, the set of instructions including instructions;

to write the N data segments in N memory portions of the first memory device, to perform an XOR operation on one or more of the N data segments, and to write a resulting XOR value in a particular memory portion of the M memory portions of the first memory device; and

transmit the sub-request to every memory portion of the M memory portions of the first memory device.

19. The non-transitory computer readable storage medium of claim 18, wherein the set of instructions in the sub-request includes information to perform an XOR operation at a first memory portion of the M memory portions using at least one data segment in the sub-request and a predefined seed value stored in the first memory portion.

20. The non-transitory computer readable storage medium of claim 18, wherein the set of instructions includes an instruction for the particular memory portion of the M memory portions to generate an XOR of all N data segments and to store the resulting XOR value in the particular memory portion.