Methods and systems for using predictive cache statistics in a storage system

• US 9,830,269 B2
• Filed: 07/29/2014
• Issued: 11/28/2017
• Est. Priority Date: 07/29/2014
• Status: Active Grant

• Current Assignee: NetApp, Inc.
• Original Assignee: NetApp, Inc.
• Inventors: McKean, Brian D., Humlicek, Donald R.
• Primary Examiner(s): Bragdon, Reginald
• Assistant Examiner(s): VO, THANH DUC
• Application Number:
  US14/445,354
• Publication Number:
  US 20160034394A1
• Time in Patent Office: 1,218 Days
• CPC Class Codes: G06F 12/0806 Multiuser, multiprocessor or multiprocessing cache systems
• CPC Class Codes: G06F 12/0862 with prefetch
• CPC Class Codes: G06F 12/0866 for peripheral storage systems, e.g. disk cache
• CPC Class Codes: G06F 12/0891 using clearing, invalidating or resetting means
• CPC Class Codes: G06F 2212/1021 Hit rate improvement
• CPC Class Codes: G06F 2212/1032 Reliability improvement, data loss prevention, degraded operation etc
• CPC Class Codes: G06F 2212/1036 Life time enhancement
• CPC Class Codes: G06F 2212/1044 Space efficiency improvement
• CPC Class Codes: G06F 2212/314 In storage network, e.g. network attached cache
• CPC Class Codes: G06F 2212/466 Metadata, control data
• CPC Class Codes: G06F 2212/601 Reconfiguration of cache memory
• CPC Class Codes: G06F 2212/6026 Prefetching based on access pattern detection, e.g. stride based prefetch
• 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: H04L 67/568 Storing data temporarily at an intermediate stage, e.g. caching
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

Method and systems for a storage system are provided. Simulated cache blocks of a cache system are tracked using cache metadata while performing a workload having a plurality of storage operations. The cache metadata is segmented, each segment corresponding to a cache size. Predictive statistics are determined for each cache size using a corresponding segment of the cache metadata. The predictive statistics are used to determine an amount of data that is written for each cache size within certain duration. The process then determines if each cache size provides an endurance level after executing a certain number of write operations, where the endurance level indicates a desired life-cycle for each cache size.

Claims

1. A method comprising:

tracking a first amount of data written to simulated cache blocks of a cache system using cache metadata while performing a workload having a plurality of storage operations during a sample period, wherein the cache metadata is segmented, each segment corresponding to a different one of a plurality of cache sizes for each of a plurality of cache devices;

extrapolating, from the first amount of data tracked for each segment of the cache metadata, a respective second amount of data to be written for each segment within a duration;

determining a number of write operations supported by each of the plurality of cache devices for the duration in which the second amount of data is to be written;

determining a minimum cache size for each of the plurality of cache devices to write the respective second amount of data for each segment, based on the number of write operations supported by that cache device and a desired life cycle for that cache device; and

selecting at least one of the plurality of cache devices for performing storage operations within the cache system, based at least in part on the minimum cache size determined for each cache device.

2. The method of claim 1, wherein the cache metadata uses a segment identifier for tracking each segment of the cache metadata.

3. The method of claim 1, wherein a storage controller tracks the simulated cache blocks of the cache system using the cache metadata.

4. The method of claim 3, wherein the simulated cache blocks of the cache system are tracked using a least recently used cache tracking mechanism.

5. The method of claim 3, wherein the simulated cache blocks of the cache system are tracked using a most recently used cache tracking mechanism.

6. The method of claim 1, further comprising:

notifying a user as to whether or not the desired life cycle for each of the plurality of cache devices is achievable based on the number of write operations supported by each cache device.

7. The method of claim 1, wherein the cache system includes a solid state cache system that operates as a secondary cache system.

8. A non-transitory machine readable medium having stored thereon instructions for performing a method comprising machine executable code which when executed by at least one machine, causes the machine to:

track a first amount of data written to simulated cache blocks of a cache system using cache metadata while performing a workload having a plurality of storage operations during a sample period, wherein the cache metadata is segmented, each segment corresponding to a different one of a plurality of cache sizes for each of a plurality of cache devices;

extrapolate, from the first amount of data tracked for each segment of the cache metadata, a respective second amount of data to be written for each segment within a duration;

determine a number of write operations supported by each of the plurality of cache devices for the duration in which the second amount of data is to be written;

determining a minimum cache size for each of the plurality of cache devices to write the respective second amount of data for each segment, based on the number of write operations supported by that cache device and a desired life cycle for that cache device; and

select at least one of the plurality of cache devices for performing storage operations within the cache system, based at least in part on the minimum cache size determined for each cache device.

9. The storage medium of claim 8, wherein the cache metadata uses a segment identifier for tracking each segment of the cache metadata.

10. The storage medium of claim 8, wherein a storage controller tracks the simulated cache blocks of the cache system using the cache metadata.

11. The storage medium of claim 10, wherein the simulated cache blocks of the cache system are tracked using a least recently used cache tracking mechanism.

12. The storage medium of claim 10, wherein the simulated cache blocks of the cache system are tracked using a most recently used cache tracking mechanism.

13. The storage medium of claim 8, the machine executable code further causing the machine to notify a user as to whether or not the desired life cycle for each of the plurality of cache devices is achievable based on the number of write operations supported by each cache device.

14. The storage medium of claim 8, wherein the cache system includes a solid state cache system that operates as a secondary cache system.

15. A computing device comprising:

a memory containing machine readable medium comprising machine executable code having stored thereon instructions for performing a method of simulating a cache system;

a processor coupled to the memory, the processor configured to execute the machine executable code to cause the processor to;

track a first amount of data written to simulated cache blocks of the cache system using cache metadata while performing a workload having a plurality of storage operations during a sample period, wherein the cache metadata is segmented, each segment corresponding to a different one of a plurality of cache sizes for each of a plurality of cache devices;

extrapolate, from the first amount of data tracked for each segment of the cache metadata, a respective second amount of data to be written for each segment within a duration; and

determine a number of write operations supported by each of the plurality of cache devices for the duration in which the second amount of data is to be written;

determining a minimum cache size for each of the plurality of cache devices to write the respective second amount of data for each segment, based on the number of write operations supported by that cache device and a desired life cycle for that cache device; and

select at least one of the plurality of cache devices for performing storage operations within the cache system, based at least in part on the minimum cache size determined for each cache device.

16. The system of claim 15, wherein the cache metadata uses a segment identifier for tracking each segment of the cache metadata.

17. The system of claim 15, wherein the simulated blocks of the cache system are tracked using cache metadata.

18. The system of claim 17, wherein the simulated cache blocks of the cache system are tracked using a most recently used cache tracking mechanism.

19. The system of claim 15, wherein a user is notified as to whether or not the desired life cycle for each of the plurality of cache devices is achievable based on the number of write operations supported by each cache device.

20. The system of claim 15, wherein the cache system includes a solid state cache system that operates as a secondary cache system.