Efficient flash memory-based object store

• US 8,725,951 B2
• Filed: 01/03/2011
• Issued: 05/13/2014
• Est. Priority Date: 04/12/2010
• Status: Active Grant

• Current Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Original Assignee: SanDisk Enterprise IP LLC (Western Digital Corporation)
• Inventors: Busch, John, Dinker, Darpan, Ouye, Darryl
• Primary Examiner(s): NGUYEN, HIEP T
• Application Number:
  US12/983,754
• Publication Number:
  US 20110252192A1
• Time in Patent Office: 1,226 Days
• US Class Current: 711/133
• CPC Class Codes: G06F 11/1446 Point-in-time backing up or restoration of persistent data
• CPC Class Codes: G06F 11/1474 in transactions G06F16/20 takes precedence
• CPC Class Codes: G06F 11/2023 Failover techniques
• CPC Class Codes: G06F 11/2071 using a plurality of controllers
• CPC Class Codes: G06F 11/2082 Data synchronisation
• CPC Class Codes: G06F 12/08 in hierarchically structured memory systems, e.g. virtual memory systems
• CPC Class Codes: G06F 16/23 Updating
• CPC Class Codes: G06F 16/24569 Query processing with adaptation to specific hardware, e.g. adapted for using GPUs or SSDs
• CPC Class Codes: G06F 3/0613 in relation to throughput
• CPC Class Codes: G06F 3/0667 at data level, e.g. file, record or object virtualisation
• 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: G06F 3/0685 Hybrid storage combining heterogeneous device types, e.g. hierarchical storage, hybrid arrays

Abstract

Approaches for an object store implemented, at least in part, on one or more solid state devices. The object store may store objects on a plurality of solid state devices. The object store may include a transaction model means for ensuring that the object store performs transactions in compliance with atomicity, concurrency, isolation, and durability (ACID) properties. The object store may include means for providing parallel flushing in a write cache maintained on each of the solid state devices. The object store may include means for maintaining one or more double-write buffers, for the object store, at a location other than the solid state devices. The object store may optionally comprise means for maintaining one or more circular transaction logs, for the object store, at a location other than the solid state devices. The object store may operate to minimize write operations performed on the solid state devices.

Claims

1. A method for durably storing data blocks maintained in a volatile cache on a solid state device, comprising:

instantiating a plurality of threads that are each configured to perform work according to one of a plurality of stages,

wherein the plurality of stages include;

a first stage in which a thread identifies, in the volatile cache of a server that issues write requests to an object store maintained on one or more solid state devices, a first set of data blocks to write to a double-write buffer cache in non-volatile dynamic random access memory (DRAM),

a second stage in which a thread writes a second set of data blocks from the volatile cache to the double-write buffer,

a third stage in which a thread writes data from the double-write buffer to the one or more solid state devices, and

wherein the plurality of threads include at least two threads that are both operating in different stages of the plurality of stages.

2. The method of claim 1, wherein the plurality of threads includes at least three threads that are each operating in a different stage of the plurality of stages.

3. The method of claim 1, wherein the plurality of threads include two or more threads that are operating in the same stage of the plurality of stages.

4. The method of claim 1, wherein the non-volatile dynamic random access memory (DRAM) is maintained in a controller of a hard-disk drive (HDD).

16. The method of claim 1, wherein instantiating the plurality of threads includes at least instantiating a first thread, and instantiating a second thread.

5. A distributed object store, comprising:

a plurality of solid state devices;

one or more processors on one or more machines; and

a machine readable medium storing one or more sequences of instructions, which when executed by the one or more processors, cause;

maintaining the distributed object store on the plurality of solid state devices, wherein the distributed object store stores objects using a transaction model that ensures compliance with atomicity, concurrency, isolation, and durability (ACID) properties;

the distributed object store providing parallel flushing in a write cache maintained on each of the plurality of solid state devices; and

the distributed object store maintaining one or more double-write buffers, for the distributed object store, at a location other than the plurality of solid state devices.

6. The distributed object store of claim 5, wherein execution of the one or more sequences of instructions by the one or more processors further cause:

the distributed object store maintaining one or more circular transaction logs, for the distributed object store, at a location other than the plurality of solid state devices.

7. The distributed object store of claim 5, wherein execution of the one or more sequences of instructions by the one or more processors further cause:

the distributed object store supporting an interface which allows an administrator to reduce a block size for the distributed object store for purposes of minimizing wear on each of the plurality of solid state devices.

8. The distributed object store of claim 5, wherein the distributed object store providing parallel flushing comprises identifying, in parallel, dirty data blocks stored within the write cache, to be replaced.

9. The distributed object store of claim 5, wherein the distributed object store is a MySQL database management system.

10. The distributed object store of claim 5, wherein the distributed object store is a memcached caching system or a non-relational data store.

11. A non-transitory machine readable storage medium storing one or more sequences of instructions for durably storing data blocks maintained in a volatile cache on a solid state device, wherein execution of the one or more sequences of instructions cause:

instantiating a plurality of threads that are each configured to perform work according to one of a plurality of stages,

wherein the plurality of stages include;

a first stage in which a thread identifies, in the volatile cache of a server that issues write requests to an object store maintained on one or more solid state devices, a first set of data blocks to write to a double-write buffer cache in non-volatile dynamic random access memory (DRAM),

a second stage in which a thread writes a second set of data blocks from the volatile cache to the double-write buffer,

a third stage in which a thread writes data from the double-write buffer to the one or more solid state devices, and

wherein the plurality of threads include at least two threads that are both operating in different stages of the plurality of stages.

12. The machine readable storage medium of claim 11, wherein the plurality of threads includes at least three threads that are each operating in a different stage of the plurality of stages.

13. The machine readable storage medium of claim 11, wherein the plurality of threads include two or more threads that are operating in the same stage of the plurality of stages.

14. The machine readable storage medium of claim 11, wherein the non-volatile dynamic random access memory (DRAM) is maintained in a controller of a hard-disk drive (HDD).

15. The machine readable storage medium of claim 11, wherein instantiating the plurality of threads includes at least instantiating a first thread, and instantiating a second thread.

17. A non-transitory computer readable storage medium storing one or more sequences of instructions, wherein execution of the one or more sequences of instructions by one or more processors cause:

maintaining a distributed object store on a plurality of solid state devices, wherein the distributed object store stores objects using a transaction model that ensures compliance with atomicity, concurrency, isolation, and durability (ACID) properties;

the distributed object store providing parallel flushing in a write cache maintained on each of the plurality of solid state devices; and

the distributed object store maintaining one or more double-write buffers, for the distributed object store, at a location other than the plurality of solid state devices.

18. The non-transitory computer readable storage medium of claim 17, wherein execution of the one or more sequences of instructions by the one or more processors further cause:

the distributed object store maintaining one or more circular transaction logs, for the distributed object store, at a location other than the plurality of solid state devices.

19. The non-transitory computer readable storage medium of claim 17, wherein execution of the one or more sequences of instructions by the one or more processors further cause:

the distributed object store supporting an interface which allows an administrator to reduce a block size for the distributed object store for purposes of minimizing wear on each of the plurality of solid state devices.

20. The non-transitory computer readable storage medium of claim 17, wherein the distributed object store providing parallel flushing comprises identifying, in parallel, dirty data blocks stored within the write cache, to be replaced.

21. The non-transitory computer readable storage medium of claim 17, wherein the distributed object store is a MySQL database management system.

22. The non-transitory computer readable storage medium of claim 17, wherein the distributed object store is a memcached caching system or a non-relational data store.