What is the severity level of a syslog message described as "system unusable" in Cisco IOS?

In Cisco IOS, syslog messages are categorized by severity levels, which range from 0 to 7. Each level corresponds to a specific type of message indicating the severity of events that occur within the system.

A syslog message with the description "system unusable" is given a severity level of 0. This level is designated as an emergency condition, meaning that the system is in an unusable state, and immediate action is required to address the issue. This is the highest level of severity, indicating that the situation is critical and that recovery or intervention is needed as soon as possible.

Other severity levels describe less critical events: Level 1 indicates alert severity; Level 2 is for critical conditions; Level 3 signifies error conditions; and so forth, with levels becoming less urgent as the number increases. All of these occupy lower severity ratings compared to the complete system failure indicated by level 0. Understanding this hierarchy is important for effective incident response and system monitoring.