Method and apparatus for monitoring the health of a computer system
View Patent ↗A system that monitors the health of a computer system is presented. During operation, the system receives a first-difference function for the variance of a time series for a monitored telemetry variable within the computer system. The system then determines whether the first-difference function indicates that the computer system is at the onset of degradation. If so, the system performs a remedial action.
1. A method for monitoring the health of a computer system, comprising:
receiving a variance of a time series for a monitored telemetry variable within the computer system,
calculating a residual function of the variance of the time series for the monitored telemetry variable;
calculating a first-difference function of the variance of the time series from the residual function;
determining whether the first-difference function indicates that the computer system is at the onset of degradation; and
if so, performing a remedial action.
2. The method of claim 1 , wherein prior to receiving the variance for the time series for the monitored telemetry variable, the method further comprises:
receiving the time series for the monitored telemetry variable; and
calculating the variance of the time series for the monitored telemetry variable.
3. The method of claim 1 , wherein calculating the first-difference function of the time series involves, for each time point within the time series, subtracting a value of the time series at a previous time point from the value of the time series at a present time point.
4. The method of claim 3 , further comprises dividing the result of the subtraction by the value of a length of a time interval between the previous time point and the present time point.
5. The method of claim 1 , wherein calculating the residual function for a time series involves:
for each time interval in the time series,
calculating a running average of values for the time series up to and including a present time interval; and
subtracting the running average from a value of the time series at the present time interval.
6. The method of claim 1 , wherein determining whether the first-difference function indicates that the computer system is at the onset of degradation involves determining whether the first-difference function exceeds a specified threshold.
7. The method of claim 1 , wherein determining whether the first-difference function indicates that the computer system is at the onset of degradation involves:
performing a Sequential Probability Ratio Test (SPRT) on the first-difference function; and
determining whether the SPRT generates an alarm.
8. The method of claim 7 , wherein the SPRT can include one or more of:
a positive variance first-difference test, which generates an alarm if the first-difference function for the variance of the time series for the monitored telemetry variable is increasing; and
a negative variance first-difference test, which generates an alarm if the first-difference function for the variance of the time series for the monitored telemetry variable is decreasing.
9. The method of claim 1 , wherein performing the remedial action can involve performing one or more of:
recording a time when the onset of degradation occurred;
notifying a system administrator that the computer system is at the onset of degradation;
shutting down the computer system;
backing up data stored on the computer system;
failing-over to a redundant computer system; and
replacing one or more components which are at the onset of degradation.
10. A computer-readable storage medium storing instructions that when executed by a computer cause the computer to perform a method for monitoring the health of a computer system, wherein the method comprises:
receiving a variance of a time series for a monitored telemetry variable within the computer system;
calculating a residual function of the variance of the time series for the monitored telemetry variable;
calculating a first-difference function of the variance of the time series from the residual function;
determining whether the first-difference function indicates that the computer system is at the onset of degradation; and
if so, performing a remedial action.
11. The computer-readable storage medium of claim 10 , prior to receiving the variance for the time series for the monitored telemetry variable, the method further comprises:
receiving the time series for the monitored telemetry variable; and
calculating the variance of the time series for the monitored telemetry variable.
12. The computer-readable storage medium of claim 10 , wherein calculating the first-difference function of the time series involves, for each time point within the time series, subtracting a value of the time series at a previous time point from the value of the time series at a present time point.
13. The computer-readable storage medium of claim 12 , wherein the method further comprises dividing the result of the subtraction by the value of a length of a time interval between the previous time point and the present time point.
14. The computer-readable storage medium of claim 10 , wherein calculating the residual function for a time series involves:
for each time interval in the time series,
calculating a running average of values for the time series up to and including a present time interval; and
subtracting the running average from a value of the time series at the present time interval.
15. The computer-readable storage medium of claim 10 , wherein determining whether the first-difference function indicates that the computer system is at the onset of degradation involves determining whether the first-difference function exceeds a specified threshold.
16. The computer-readable storage medium of claim 10 , wherein determining whether the first-difference function indicates that the computer system is at the onset of degradation involves:
performing a Sequential Probability Ratio Test (SPRT) on the first-difference function; and
determining whether the SPRT generates an alarm.
17. The computer-readable storage medium of claim 16 , wherein the SPRT can include one or more of:
a positive variance first-difference test, which generates an alarm if the first-difference function for the variance of the time series for the monitored telemetry variable is increasing; and
a negative variance first-difference test, which generates an alarm if the first-difference function for the variance of the time series for the monitored telemetry variable is decreasing.
18. The computer-readable storage medium of claim 10 , wherein performing the remedial action can involve performing one or more of:
recording a time when the onset of degradation occurred;
notifying a system administrator that the computer system is at the onset of degradation;
shutting down the computer system;
backing up data stored on the computer system;
failing-over to a redundant computer system; and
replacing one or more components which are at the onset of degradation.
19. An apparatus that monitors the health of a computer system, comprising:
a receiving mechanism configured to receive a variance of a time series for a monitored telemetry variable within the computer system,
a residual-calculation mechanism configured to calculate a residual function of the variance of the time series for the monitored telemetry variable;
a difference-calculation mechanism configured to calculate a first-difference function of the variance of the time series from the residual function;
a degradation-detection mechanism configured to determine whether the first-difference function indicates that the computer system is at the onset of degradation; and
a remedial-action mechanism, wherein if the degradation-detection mechanism determines that the computer system is at the onset of degradation, the remedial-action mechanism is configured to perform a remedial action.