Availability as a quality attribute: strategies for fault detection

Availability is a property of a service that describes its availability at the time when it is needed. Troubleshooting is the first step to ensuring high availability.

Troubleshooting tactics help the system identify possible problems and respond to them quickly. Let’s consider the main approaches:
🔹 Monitor
A separate component of the system monitors the status of services: processors, memory, I/O, network connections, etc. This allows you to quickly identify potential problems before they become critical, especially if this component is part of the service process.
🔹 Ping/Echo
Used to check the availability of components on the network. This is an asynchronous request-response mechanism that allows you to determine whether a node is up and running, as well as estimate delays.
🔹 Heartbeat
A mechanism for periodic notifications from system components. If the process stops sending “life signals”, the system considers it a failure.
🔹 Condition Monitoring
Analyzes the conditions of process execution or checks the correctness of calculations to prevent incorrect behavior. Checksums are the most common example.
🔹 Sanity Checking
Evaluates the validity of results or input data to avoid errors in the logic of components. For example, validation schemes are prepared.
🔹 Voting
Compares results from multiple sources and selects the correct one, reducing the risk of failures due to erroneous calculations.
🔹 Exception Detection
Provides various mechanisms for intercepting and handling exceptional situations, such as timeouts or checking the validity of parameter values.
🔹 Self-Test
The system components periodically run checks to make sure that their operation is correct.

Implementation of fault detection tactics allows you to:
-Reduce the risk of sudden failures;
-Respond quickly to potential problems;
-Minimize downtime and data loss;
-Increase the reliability and predictability of the system.

Availability directly depends on the system’s ability to recognize faults before they have a critical impact. By using these tactics, you create a reliable IT environment that can withstand any challenge. 🚀