Software rejuvenation is a technique that aims to prevent or delay software failures due to software aging, which is the degradation of software performance or reliability over time due to memory leaks, resource exhaustion, data corruption, etc. Software rejuvenation works by periodically restarting the software system or application to restore it to a clean and fresh state, thereby releasing the resources and removing the errors that may have accumulated over time.
To measure the effectiveness of software rejuvenation, you need to consider several factors, such as:
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The type and characteristics of the software system or application that needs rejuvenation. For example, some software systems may have more complex or dynamic interactions with other components or resources, which may require more sophisticated or adaptive rejuvenation models and policies.
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The availability and reliability of data and information about the software behavior and performance. For example, some software systems may have more accurate or frequent monitoring and measurement of their resource usage, error rates, response times, etc., which may enable more effective or optimal rejuvenation decisions.
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The trade-offs and objectives of the software rejuvenation process. For example, some software systems may have different requirements or preferences for the availability, reliability, maintainability, cost, or lifespan of the software, which may affect the choice of rejuvenation frequency, timing, or method.
Based on these factors, you may want to use different metrics to measure the effectiveness of software rejuvenation, such as:
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Availability: This metric measures the proportion of time that the software system or application is operational and ready to provide its intended services. Software rejuvenation can improve availability by reducing the frequency and severity of software failures due to aging effects.
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Reliability: This metric measures the probability that the software system or application will perform its intended functions without failure for a given period of time. Software rejuvenation can improve reliability by preventing or delaying the occurrence of software aging effects that may cause incorrect or inconsistent results.
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Performance: This metric measures the quality or efficiency of the software system or application in terms of its response time, throughput, resource utilization, etc. Software rejuvenation can improve performance by restoring the system to a clean and fresh state that can handle requests faster and more effectively.
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Cost: This metric measures the total amount of money spent on developing, operating, maintaining, and repairing the software system or application. Software rejuvenation can reduce cost by lowering the need for corrective actions or repairs after a software failure occurs. However, software rejuvenation also incurs some cost due to the downtime and disruption caused by rejuvenation actions.
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Lifespan: This metric measures the duration of time that the software system or application can continue to provide its intended services before it becomes obsolete or incompatible with changing user needs and technology platforms. Software rejuvenation can extend lifespan by keeping the system up-to-date and compatible with new requirements and environments.
To determine the optimal rejuvenation strategy, most existing works focus on the modeling of aging process and evaluating the strategy in terms of traditional dependability metrics such as reliability and availability. However, some recent works also consider other metrics such as performance and cost to capture the trade-offs and objectives of different scenarios and applications. For example:
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On the performance of software rejuvenation models with multiple degradation levels: This paper proposes to model software systems’ overall performance capacity by assigning a performance capacity level at each of the possible states that it can be in, using a continuous time Markov process. A performance capacity indicator for all possible rejuvenation models incorporating partial, full, or both rejuvenation actions is defined and evaluated in the transient and steady state phase. The paper also formulates multi-objective optimization problems for deriving the rejuvenation policies that optimize the system’s overall performance capacity with respect to availability and operational cost constraints.
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Software Aging and Rejuvenation for Increased Resilience: Modeling, Analysis and Applications: This chapter presents an overview of important analytical models and measurement approaches for software aging and rejuvenation. It also presents measurement based approaches using both online and offline methods for software rejuvenation. The chapter also presents a categorization of the approaches and their applicability for different domains and scenarios.
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Software aging and rejuvenation in android: new models and metrics: This paper investigates software aging phenomena in Android applications using empirical data collected from real devices. It also proposes new stochastic models for Android applications that consider both user interactions and background activities as sources of aging effects. The paper also introduces new metrics for evaluating Android applications’ availability, reliability, performance degradation rate, energy consumption rate, etc.