Software Architecture - Availability

These flashcards cover key terms and concepts related to the topic of availability in software architecture.

Availability

A property of software that indicates it is ready to perform its tasks when needed.

Reliability

The ability of an item to perform a required function under stated conditions for a specified time.

Dependability

The ability to avoid failures that are more frequent or severe than acceptable.

Fault

The cause of a failure, which can be either internal or external to the system.

Mean Time Between Failures (MTBF)

The average time between inherent failures of a system.

Mean Time To Repair (MTTR)

The average time required to repair a system and restore it to working condition.

Fault Tree Analysis

An analytical technique to identify all the ways an undesired state could occur.

Failure Mode, Effects, and Criticality Analysis (FMECA)

A method that catalogs types of failures and assesses their severity and impact.

High Availability

Refers to designs targeting availability of 99.999 percent or greater.

Hazard Analysis

A technique to catalog hazards during system operation and assess their severity.

Fault Detection

The identification of faults before they lead to failures.

Fault Recovery

Processes used to rectify faults and return to normal operation.

Fault Prevention

Measures taken to avert faults from occurring in the first place.

Service-Level Agreements (SLAs)

Contracts that outline expected availability and performance of services.

Denial-of-Service Attack

A malicious attempt to disrupt the normal functioning of a targeted server.

Resilience

The ability of a system to withstand faults without failing.

Degraded Mode

Operation mode where a system continues to function but with reduced capacity.

Design Checklist for Availability

A tool to support the design and analysis of system availability.