COIS 3040H Lecture 7: WEEK 7 LEC NOTES

• School: Trent University
• Department: Computing & Information Systems
• Course: COIS 3040H
• Professor: Omar

Document Summary

Availability tactics for non functional requirements: tactics to detect faults, ping/echo, monitor, heartbeat, timestamp, timeout, self test. Tactics to recover from faults: preparation and repair. Active redundancy (hot spare) all nodes (active or redundant spare) in the system are active. Passive redundancy (warm spare) only the active members of the protection group process input traffic; one of their duties is to provide the redundant spare(s) with periodical state updates *most common. Spare (cold spare) the redundant spares of a protection group remain out of service until a fail-over occurs, at which point a power-on-rest procedure is initiated on the redundant spare prior to its being placed in service. Exception handling once an exception has been detected , the system must handle it in some fashion. Rollback permits reverting the system to a previous healthy state. Software upgrade - in-service upgrades to executable code images in a non-service affecting manner.