Solid state storage subsystem that maintains and provides access to data reflective of a failure risk

• US 8,078,918 B2
• Filed: 02/07/2008
• Issued: 12/13/2011
• Est. Priority Date: 02/07/2008
• Status: Active Grant

• Current Assignee: JP Morgan Chase Bank, N.A. (JP Morgan Chase & Co)
• Original Assignee: SiliconSystems, Inc. (Western Digital Corporation)
• Inventors: Diggs, Mark S., Merry, David E. Jr.
• Primary Examiner(s): CHU, GABRIEL L
• Application Number:
  US12/027,965
• Publication Number:
  US 20090204852A1
• Time in Patent Office: 1,405 Days
• Field of Search: None
• US Class Current: 714/42
• CPC Class Codes: G06F 11/008 Reliability or availability analysis

Abstract

A storage subsystem is disclosed that maintains (a) statistics regarding errors detected via an ECC (error correction code) module of the storage subsystem; and/or (b) historical data regarding operating conditions experienced by the storage subsystem, such as temperature, altitude, humidity, shock, and/or input voltage level. The storage subsystem, and/or a host system to which the storage subsystem attaches, may analyze the stored data to assess a risk of a failure event such as an uncorrectable data error. The results of this analysis may be displayed via a user interface of the host system, and/or may be used to automatically take a precautionary action such as transmitting an alert message or changing a mode of operation of the storage subsystem.

Claims

1. A storage subsystem, comprising:

a solid-state, non-volatile memory array;

a connector for attaching the storage subsystem to a host system;

at least one sensor that collects data related to at least one type of environmental condition including one or more of conditions related to temperature, humidity, altitude, shock, and power; and

a controller configured to write data to and read data from the non-volatile memory array in response to commands received from the host system, said controller configured to generate and store data on write operations, and to use error correction code (ECC) data to check for and correct errors on read operations;

wherein the storage subsystem is configured to;

maintain statistical data, based at least in part on the ECC data, that is reflective of a rate at which errors are detected on said read operations, and event timestamp data that is correlated to the statistical data;

when the rate at which said errors are detected exceeds a threshold during a time period in which a write operation is performed, store condition data reflective of a condition of the storage subsystem with data written by the write operation; and

provide said statistical data, said data collected by the at least one sensor, said condition data, and said event timestamp data to the host system via said connector, the storage subsystem thereby enabling the host system to monitor a health of the storage subsystem and to use the event timestamp data and the condition data to correlate an increased rate of errors with an environmental condition observed by the at least one sensor.

2. The storage subsystem of claim 1, wherein the statistical data comprises a first value that indicates a number of write operations performed, and a second value that indicates a total number of errors corrected.

3. The storage subsystem of claim 2, wherein the statistical data further comprises a plurality of counter values, each of which corresponds to a different respective number of bits errors on a read operation.

4. The storage subsystem of claim 1, wherein the statistical data comprises a value that represents a bit error rate of the storage subsystem.

5. The storage subsystem of claim 1, wherein the controller is configured to analyze the statistical data to assess a risk of a failure event.

6. The storage subsystem of claim 5, wherein the controller is configured to modify a mode of operation of the storage subsystem when said risk of a failure event reaches a threshold level, to thereby reduce a likelihood of a failure event occurring.

7. The storage subsystem of claim 1, wherein the controller implements an Advanced Technology Attachment (ATA) command set, and implements at least one vendor-specific command that enables the host system to retrieve the statistical data.

8. The storage subsystem of claim 1, in combination with executable code configured to run on the host system, said executable code configured to display at least some of said statistical data, and/or a risk indicator derived therefrom, on a display of the host system.

9. The storage subsystem of claim 1, wherein the controller maintains said statistical data in a restricted area of the non-volatile memory array.

10. The storage subsystem of claim 1, wherein the controller is further configured to detect, and store data regarding, correlations between environmental conditions sensed by said sensor and errors detected via said ECC checking.

11. The storage subsystem of claim 1, wherein the controller is further configured to maintain, and output to the host system, data regarding an amount of time the storage subsystem has been powered up.

12. The storage subsystem of claim 1, wherein the controller is further configured to maintain, and output to the host system, data regarding a stability of a power signal received from the host system.

13. The storage subsystem of claim 1, wherein the controller is further configured to maintain historical measurement data reflective of said measurements in the non-volatile memory array, and output said historical measurement data to the host system.

14. The storage subsystem of claim 1, wherein the at least one sensor comprises a temperature sensor.

15. The storage subsystem of claim 1, wherein the at least one sensor comprises an altitude sensor.

16. The storage subsystem of claim 1, wherein the at least one sensor comprises a shock sensor.

17. The storage subsystem of claim 1, wherein the at least one sensor comprises a humidity sensor.

18. The storage subsystem of claim 1, in combination with the host system, wherein the host system is programmed to use the statistical and timestamp data received from the storage subsystem to determine whether a correlation exists between an increased error rate and a sensed environmental condition.

19. The storage subsystem of claim 18, wherein the environmental condition is a temperature of the storage subsystem and the host system is further configured to adjust a mode of operation of the storage subsystem to effect a change in the temperature.

20. A method for monitoring data error in a storage subsystem, the method comprising:

generating and storing error correction code (ECC) data descriptive of write data received by the storage subsystem from a host system, and storing said write data and ECC data in a non-volatile solid state memory array of the storage subsystem;

performing ECC checking of said write data and ECC data when the write data is subsequently read from the non-volatile solid state memory array, said ECC checking performed by an ECC module of the storage subsystem;

collecting, via a sensor, data related to at least one type of environmental condition including one or more of conditions related to temperature, humidity, altitude, shock, and power;

maintaining statistical data in said storage subsystem reflective of a rate at which errors are detected by the ECC module and event timestamp data that is correlated to the statistical data; and

when the rate detected by the ECC module exceeds a threshold during a time period in which a write operation is performed, writing condition data reflective of a condition of the storage subsystem to the non-volatile solid state memory array with data written by the write operation; and

using said statistical data, said data collected by the sensor, said condition data, and said event timestamp data to monitor a health of the storage subsystem and determine a correlation between an increased rate of errors and an environmental condition observed by the sensor.

21. The method of claim 20, further comprising programmatically analyzing the statistical data to assess a risk of a storage subsystem failure.

22. The method of claim 20, wherein the environmental condition is a temperature of the storage subsystem and the method further comprises:

adjusting a mode of operation of the storage subsystem to effect a change in the temperature.

23. A storage subsystem, comprising:

a solid-state, non-volatile memory array;

a connector for attaching the storage subsystem to a host system;

at least one sensor that collects data related to at least one type of environmental condition including one or more of conditions related to temperature, humidity, altitude, shock, and power; and

a controller configured to write data to and read data from the non-volatile memory array in response to commands received from the host system, said controller configured to generate and store data on write operations, and to use error correction code (ECC) data to check for and correct errors on read operations;

wherein the storage subsystem is configured to;

maintain statistical data, based at least in part on the ECC data, that is reflective of a rate at which errors are detected on said read operations;

in response to the rate at which said errors are detected exceeding a threshold during a time period in which a write operation is performed, store condition data reflective of a condition of the storage subsystem with data written by the write operation; and

provide said statistical data, said data collected by the at least one sensor and said condition data to the host system via said connector, the storage subsystem thereby enabling the host system to monitor a health of the storage subsystem and to use the condition data to correlate an increased rate of errors with an environmental condition observed by the at least one sensor.