Apparatus, system, and method for solid-state storage as cache for high-capacity, non-volatile storage

• US 8,285,927 B2
• Filed: 08/05/2011
• Issued: 10/09/2012
• Est. Priority Date: 12/06/2006
• Status: Active Grant

• Current Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Original Assignee: Fusion-IO Incorporated (Western Digital Corporation)
• Inventors: Flynn, David, Strasser, John, Thatcher, Jonathan, Zappe, Michael
• Primary Examiner(s): Dudek, Jr., Edward
• Assistant Examiner(s): Fishburn, John P
• Application Number:
  US13/204,551
• Publication Number:
  US 20110289267A1
• Time in Patent Office: 431 Days
• Field of Search: None
• US Class Current: 711/113
• CPC Class Codes: G06F 1/183 Internal mounting support structures, e.g. for printed circuit boards, internal connecting means for buses G06F13/409
• CPC Class Codes: G06F 11/108 Parity data distribution in semiconductor storages, e.g. in SSD
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 12/0804 with main memory updating G06F12/0806 takes precedence
• CPC Class Codes: G06F 12/0868 Data transfer between cache memory and other subsystems, e.g. storage devices or host systems
• CPC Class Codes: G06F 12/12 Replacement control
• CPC Class Codes: G06F 12/121 using replacement algorithms
• CPC Class Codes: G06F 12/123 with age lists, e.g. queue, most recently used [MRU] list or least recently used [LRU] list
• CPC Class Codes: G06F 13/28 using burst mode transfer, e.g. direct memory access DMA, cycle steal G06F13/32 takes precedence
• CPC Class Codes: G06F 13/4022 using switching circuits, e.g. switching matrix, connection or expansion network G06F13/4009 takes precedence
• CPC Class Codes: G06F 13/426 using an embedded synchronisation, e.g. Firewire bus, Fibre Channel bus, SSA bus
• CPC Class Codes: G06F 2211/002 Bus
• CPC Class Codes: G06F 2211/103 Hybrid, i.e. RAID systems with parity comprising a mix of RAID types
• CPC Class Codes: G06F 2212/1032 Reliability improvement, data loss prevention, degraded operation etc
• CPC Class Codes: G06F 2212/1044 Space efficiency improvement
• CPC Class Codes: G06F 2212/2022 Flash memory
• CPC Class Codes: G06F 2212/222 Non-volatile memory
• CPC Class Codes: G06F 2212/70 Details relating to dynamic memory management
• CPC Class Codes: G06F 2212/7203 Temporary buffering, e.g. using volatile buffer or dedicated buffer blocks
• CPC Class Codes: G06F 2212/7205 Cleaning, compaction, garbage collection, erase control
• CPC Class Codes: G06F 2212/7208 : Multiple device management, e.g. distributing data over multiple flash devices
• CPC Class Codes: G06F 3/0604 : Improving or facilitating administration, e.g. storage management
• CPC Class Codes: G06F 3/0608 : Saving storage space on storage systems
• CPC Class Codes: G06F 3/0613 : in relation to throughput
• CPC Class Codes: G06F 3/0619 : in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/0643 : Management of files
• CPC Class Codes: G06F 3/065 : Replication mechanisms
• CPC Class Codes: G06F 3/0652 : Erasing, e.g. deleting, data cleaning, moving of data to a wastebasket
• 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 3/0685 : Hybrid storage combining heterogeneous device types, e.g. hierarchical storage, hybrid arrays
• CPC Class Codes: G06F 3/0688 : Non-volatile semiconductor memory arrays
• CPC Class Codes: G06F 9/52 : Program synchronisation; Mutual exclusion, e.g. by means of semaphores
• CPC Class Codes: G06F 9/54 : Interprogram communication
• CPC Class Codes: H04L 67/02 : based on web technology, e.g. hypertext transfer protocol [HTTP]
• CPC Class Codes: H04L 67/1097 : for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS]
• CPC Class Codes: H05K 7/1444 : Complex or three-dimensional-arrangements; Stepped or dual mother boards
• CPC Class Codes: H05K 7/1487 : Blade assemblies, e.g. blade cases or inner arrangements within a blade
• CPC Class Codes: Y02D 10/00 : Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

An apparatus, system, and method are disclosed for solid-state storage as cache for high-capacity, non-volatile storage. The apparatus, system, and method are provided with a plurality of modules including a cache front-end module and a cache back-end module. The cache front-end module manages data transfers associated with a storage request. The data transfers between a requesting device and solid-state storage function as cache for one or more HCNV storage devices, and the data transfers may include one or more of data, metadata, and metadata indexes. The solid-state storage may include an array of non-volatile, solid-state data storage elements. The cache back-end module manages data transfers between the solid-state storage and the one or more HCNV storage devices.

Claims

1. A method for caching data, comprising:

coupling a plurality of solid-state storage elements in parallel to a storage controller of a solid-state storage device; and

configuring the storage controller to cache data on the solid-state storage device in response to storage requests directed to a high-capacity non-volatile storage device, wherein configuring the storage controller further comprises configuring the storage controller to store data of a storage request directed to the high-capacity non-volatile storage device on the plurality of solid-state storage elements by issuing a single write command to the plurality of solid-state storage elements in parallel and to associate the data with a sequence indicator that defines an ordered sequence of storage operations for a logical identifier of the data, the single write command configured to write data of the storage request on respective physical storage locations of the plurality of solid-state storage elements in parallel and in response to the single write command.

2. The method of claim 1, further comprising configuring the storage controller to store the data in a format that associates the data with respective logical identifiers.

3. The method of claim 1, further comprising configuring the storage controller to associate sequence indicators with storage divisions of the solid-state storage device, wherein the sequence indicators determine an ordered sequence of the storage divisions.

4. The method of claim 3, further comprising configuring the storage controller to:

store the data in a format that associates the data with respective logical identifiers on the solid-state storage device;

maintain an index of associations between logical identifiers of the data and physical storage locations comprising the data on the solid-state storage device; and

reconstruct the index using the logical identifiers and the sequence indicators on the solid-state storage device.

5. The method of claim 4, wherein the logical identifiers associated with the data correspond to an address of the data on a high-capacity non-volatile storage device.

6. The method of claim 4, wherein reconstructing the index comprises replaying a sequence of changes made to the index using the logical identifiers and the sequence indicators on the solid-state storage device.

7. The method of claim 1, further comprising configuring the storage controller to mark storage divisions of the solid-state storage device with respective sequence indicators.

8. The method of claim 1, further comprising configuring the storage controller to:

store data in an error-correcting code (ECC) block comprising at least a portion of the data and an error-correcting code to correct errors in the ECC block;

store a first portion of the ECC block on a first one of the solid-state storage elements; and

store a second portion of the ECC block on a second one of the solid-state storage elements.

9. The method of claim 1, further comprising configuring the storage controller to:

packetize the data of the storage requests directed to the high-capacity non-volatile storage device into one or more packets, each packet having a header comprising a logical identifier associated with the data; and

store the one or more packets sequentially on the solid-state storage device.

10. The method of claim 9, further comprising configuring the storage controller to:

store a first portion of a packet on a first one of the solid-state storage elements; and

store a second portion of the packet on a second one of the solid-state storage elements.

11. The method of claim 9, further comprising configuring the storage controller to:

store a first portion of a packet on a first one of the solid-state storage elements and a second portion of the packet on a second one of the solid-state storage elements in response to a single write command.

12. The method of claim 1, wherein a write execution time of the solid-state storage media is greater than a read execution time of the solid-state storage media, the method further comprising configuring the storage controller to:

buffer the data of the storage requests directed to the high-capacity non-volatile storage device on a write data buffer; and

store the buffered data on a logical page of the solid-state storage media, the logical page comprising physical pages on each of the plurality of solid-state storage elements.

13. The method of claim 12, wherein the solid-state storage elements of the logical pages are arranged in parallel, and wherein the buffered data is stored on the plurality of solid-state storage elements comprising the logical page in response to a single write command issued to each of the solid-state storage elements in parallel.

14. The method of claim 1, wherein the solid-state storage media is a write-once storage media, and wherein an erase execution time of the solid-state storage media is greater than a write execution time of the solid-state storage media, the method further comprising configuring the storage controller to erase a logical storage division comprising a plurality of logical pages of the solid-state storage elements in parallel.

15. The method of claim 1, further comprising configuring the storage controller to:

partition a solid-state storage device into a first portion and a second portion;

store the data of the storage requests directed to the high-capacity non-volatile storage device in the first portion of the solid-state storage device; and

store data of storage requests directed to the solid-state storage device in the second portion of the solid-state device.

16. The method of claim 15, wherein the data of the storage requests directed to the high-capacity non-volatile storage device are stored on a storage division of a solid-state storage media of the solid-state storage device with the data of the storage requests directed to the solid-state storage device.

17. The method of claim 1, further comprising configuring the storage controller to store cache control metadata sequentially with the data of the storage requests directed to the high-capacity non-volatile storage device on the solid-state storage device.

21. The method of claim 1, wherein one or more of the plurality of solid-state storage elements are in different chips, and wherein coupling the plurality of solid-state storage elements in parallel to the storage controller comprises coupling each of the solid-state storage elements to the storage controller by way of a respective, independent bus.

18. A non-transitory computer-readable storage medium comprising instructions to cause a computing device to perform a method, the method comprising:

caching data in response to storage requests to a high-capacity non-volatile storage device;

wherein caching comprises storing data of a storage request directed to the high-capacity non-volatile storage device on a solid-state storage device comprising a plurality of solid-state storage elements by issuing a single write command to the plurality of solid-state storage elements in parallel and associating the data with a sequence indicator that defines an ordered sequence of storage operations for a logical identifier of the data, the single write command configured to write data of the storage request on respective physical storage locations of the plurality of solid-state storage elements in parallel and in response to the single write command.

19. The non-transitory computer-readable storage medium of claim 18, the method further comprising marking storage divisions of the solid-state storage device comprising the data of the storage requests directed to the high-capacity non-volatile storage device with respective sequence numbers to determine a temporal order of the storage divisions.

20. A solid-state storage device to cache data for a high-capacity non-volatile (HCNV) storage device, comprising:

a plurality of solid-state storage elements coupled in parallel to a storage controller;

a cache front-end module to manage data transfers between the storage controller and a requesting device;

a cache back-end module to manage data transfers between the storage controller and a HCNV storage device, the data being associated with respective logical identifiers by the requesting device and the HCNV; and

a sequential storage module to store data of the HCNV storage device on the solid-state storage elements, by issuing a single write command to the solid-state storage elements in parallel and to associate the data with a sequence indicator that defines an ordered sequence of storage operations for a logical identifier of the data, the single write command configured to store data of the HCNV storage device on respective physical storage locations of each of the plurality of solid-state storage elements in parallel and in response to the single write command, and

wherein the sequential storage module is configured to store sequence indicators and the respective logical identifiers of the data on the solid-state storage elements in association with the data, wherein the sequence indicators persist the order of storage operations performed on the solid-state storage elements, and wherein the logical identifiers persist associations between the data and the respective logical identifiers of the data.