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

Patent metadata

Field	Value
Publication number	US-9830269-B2
Application number	US-201414445354-A
Country	US
Kind code	B2
Filing date	Jul 29, 2014
Priority date	Jul 29, 2014
Publication date	Nov 28, 2017
Grant date	Nov 28, 2017

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.

First claim

What is claimed is:

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.

Assignees

• Netapp Inc
• Netapp Inc

Inventors

• Mckean Brian D
• Humlicek Donald R

Classifications

• G06F2212/1044

  Space efficiency improvement · CPC title

• G06F12/0866 Primary

  for peripheral storage systems, e.g. disk cache · CPC title

• G06F2212/601

  Reconfiguration of cache memory · CPC title

• G06F2212/314

  In storage network, e.g. network attached cache · CPC title

• G06F2212/1032

  Reliability improvement, data loss prevention, degraded operation etc · CPC title