APPARATUS, SYSTEM, AND METHOD FOR SOLID-STATE STORAGE AS CACHE FOR HIGH-CAPACITY, NON-VOLATILE STORAGE

• US 20110289267A1
• Filed: 08/05/2011
• Published: 11/24/2011
• 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, Thatcher, Jonathan, Zappe, Michael, Strasser, John
• Granted Patent: US 8,285,927 B2
• Time in Patent Office: Days
• US Class Current: 711/103
• 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:

providing a solid-state storage device configured to overcome differences in execution time for storage operations;

caching data on the solid-state storage device in response to storage requests directed to a high-capacity non-volatile storage device; and

storing cache data sequentially on a solid-state storage media of the solid-state storage device to preserve an ordered sequence of storage operations performed on the solid-state storage media.

2. The method of claim 1, further comprising storing the cache data in a format that associates the cache data with respective logical identifiers of the cache data on the solid-state storage media.

3. The method of claim 1, further comprising associating sequence indicators with the cache data on the solid-state storage media, wherein the sequence indicators determine an ordered sequence of storage operations performed on the solid-state storage media.

4. The method of claim 3, further comprising:

storing the cache data in a format that associates the cache data with respective logical identifiers on the solid-state storage media;

maintaining an index of associations between logical identifiers of the cache data and physical storage locations comprising the cache data on the solid-state storage media; and

reconstructing the index using the logical identifiers and the sequence indicators associated with the cache data on the solid-state storage media.

5. The method of claim 1, wherein the logical identifiers associated with the cache data correspond to an address of the cache data on a high-capacity non-volatile storage device.

6. The method of claim 1, wherein reconstructing the index comprises replaying a sequence of changes made to the index using the logical identifiers and the sequence indicators associated with the cache data on the solid-state storage media.

7. The method of claim 1, wherein storing cache data on the solid-state storage media comprises marking storage divisions of the solid-state storage media with the respective sequence indicators.

8. The method of claim 1, further comprising:

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

storing a first portion of the ECC block on a first storage element of the solid-state storage media; and

storing a second portion of the ECC block on a second storage element of the solid-state storage media.

9. The method of claim 1, further comprising:

packetizing the cache data into one or more packets, each packet having a header comprising a logical identifier associated with the cache data; and

storing the one or more packets sequentially on the solid-state storage media.

10. The method of claim 9, further comprising:

storing a first portion of a packet on a first storage element of the solid-state storage media; and

storing a second portion of the packet on a second storage element of the solid-state storage media.

11. The method of claim 9, further comprising:

storing a first portion of a packet on a first storage element of the solid-state storage media and a second portion of the packet on a second storage element of the solid-state storage media 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:

buffering cache data on a write data buffer;

storing the buffered cache data on a logical page of the solid-state storage media, the logical page comprising physical pages on each of a 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 cache data is stored on the plurality of solid-state storage elements comprising the logical page in response to a single write command.

14. The method of claim 12, 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 erasing 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:

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

storing the cache data in the first portion of the solid-state storage device; and

storing non-cache data in the second portion of the solid-state device.

16. The method of claim 15, wherein the portion of the cache data is stored on a storage division of a solid-state storage media of the solid-state storage device with non-cache data.

17. The method of claim 1, further comprising storing cache control metadata pertaining to the cache data sequentially with the cache data on the solid-state storage device.

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 the cache data is associated with respective logical identifiers;

storing cache data on a solid-state storage device sequentially in a format that associates the cache data with respective logical identifiers and respective sequence indicators on the solid-state storage media, wherein the sequence indicators determine an ordered sequence of storage operations performed on the solid-state storage media.

19. The non-transitory computer-readable storage medium of claim 19, further comprising marking storage divisions of the solid-state storage device comprising the cache data 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 cache front-end module to manage cache data transfers between the solid-state storage device and a requesting device;

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

a sequential storage module to store cache data of the HCNV storage device on a solid-state storage media, wherein the sequential storage module stores sequence indicators and the respective logical identifiers of the cache data on the solid-state storage media in association with the cache data, wherein the sequence indicators persist the order of storage operations performed on the solid-state storage media, and wherein the logical identifiers persist associations between the cache data and the respective logical identifiers of the cache data.