Use the show logging command to troubleshoot stacking problems

Cause

The show logging command troubleshoots problems in stacking.

Syntax 

show logging [a|r|m|e|p|w|i|d|filter|substring]
The options a|r|substring can be used in combination with an event class option.
a

Instructs the switch to display all recorded log events, which includes events from previous boot cycles.

r

Instructs the switch to display recorded log events in reverse order (most recent first.)

filter

Instructs the switch to display log filter configuration and status information.

substring

Instructs the switch to display only those events that match the substring.

The remaining event class options are listed in order of severity with lowest severity first. The output of the command is confined to event classes of equal or higher severity.

Only one of options d|i|w|e|p|m can be used in the command at a time.
m

Displays major type of messages.

e

Displays major and error type of messages.

p

Displays major, error, and performance event type of messages.

w

Displays major, error, performance, and warning type of messages.

i

Displays major, error, performance, warning, and information.

d

Displays major, error, performance, warning, information, and debug messages.

Logging output 

switch#: show logging -r -s
I 10/02/00 00:46:56 02558 chassis: ST1-STBY: Stack port 3 is now on-line.
I 10/02/00 00:46:56 02558 chassis: ST2-CMDR: Stack port 2 is now on-line.