64
system operation and detecting abnormal states.
Note: the NVRAM log buffer may not exist on some switches, which only
have the SDRAM log buffer zone
It is recommended to use the system log server. By configuring the log host
on the switch, the log can be sent to the log server for future examination
2.2.9.1.2 Format And Severity Of The Log Information
The log information format is compatible with the BSD syslog protocol, so we can
record and analyze the log by the systlog (system log protect session) on the
UNIX/LINUX, as well as syslog similar applications on PC.
The log information is classified into eight classes by severity or emergency
procedure. One level per value and the higher the emergency level the log information
has, the smaller its value will be. For example, the level of critical is 2, and warning is 4,
debugging is leveled at 7, so the critical is higher than warnings which no doubt is high
than debugging. The rule applied in filtering the log information by severity level is that:
only the log information with level equal to or higher than the threshold will be outputted.
So when the severity threshold is set to debugging, all information will be outputted and if
set to critical, only critical, alerts and emergencies will be outputted.
Follow table summarized the log information severity level and brief description.
Note: these severity levels are in accordance with the standard UNIX/LINUX syslog
Table 1-1 Severity of the log
ٛ
information
Severity Value
Description
emergencies 0
System is unusable
alerts 1
Action must be taken immediately
critical 2
Critical conditions
errors 3
Error conditions
warnings 4
Warning conditions
notifications 5
Normal but significant condition
informational 6
Informational messages
debugging 7
Debug-level messages
Right now the switch can generate information of following four levels
z
Restart the switch, mission abnormal, hot plug on the CHASSIS switch chips are
classified critical
z
Up/down switch, topology change, aggregate port state change of the interface
are classified warnings
z
Outputted information from the CLI command is classified informational
