Table 1 Example of fault tolerance specification using the guidelines
From: Designing fault-tolerant SOA based on design diversity
Failure mode | Fault latency | Fault assumption | How to tolerate |
|---|---|---|---|
Delay | Permanent | Inefficient Algorithm | Change the faulty service to another one |
Hardware problem | Change the application server | ||
Transient | Server overload | Change the application server | |
Intermittent | Environmental instability | Execution in parallel to get the fastest reply | |
Output | Permanent | Software bug | Use variant services to detect and majority election to tolerate |
Transient | Server overload | Use variant services to detect and majority election to tolerate | |
Intermittent | Electromagnetic interference | Use variant services to detect and majority election to tolerate | |
Specification | Permanent | Malicious service | Use variant services to detect and majority |
election to tolerate | |||
Transient | DNS mistake due to environmental instability | Use variant services to detect and majority election to tolerate | |
Intermittent | Unknown cause | Use variant services to detect and majority election to tolerate | |
Server | Permanent | Hardware failure | Change the application to a mirror server |
Transient | Memory overload | Change the application to a mirror server | |
Intermittent | Environmental instability | Use redundant servers in parallel, and synchronisation algorithms for keeping the consistency among servers | |
Communication | Permanent | Breaking the optical fibber cable | Change the network link |
Transient | Network overload | Change the network link | |
Intermittent | Electromagnetic interference | Use redundant communication channel in parallel |