Generating Debug Command Output; Redirecting Debug And Error Message Output - Cisco AJ732A - MDS 9134 Fabric Switch Command Reference Manual

Chapter 1 CLI Overview
S e n d d o c u m e n t a t i o n c o m m e n t s t o m d s f e e d b a c k - d o c @ c i s c o . c o m
Using the no debug all command is a convenient way to ensure that you have not accidentally left any
debug commands turned on.
Because debugging output takes priority over other network traffic, and because the debug all command
Caution
generates more output than any other debug command, it can severely diminish the performance of the
router or even render it unusable. In virtually all cases, it is best to use more specific debug commands.

Generating debug Command Output

Enabling a debug command can result in output similar to the following example for the debug modem
command:
Router# debug modem
15:25:51: TTY4: DSR came up
15:25:51: tty4: Modem: IDLE->READY
15:25:51: TTY4: Autoselect started
15:27:51: TTY4: Autoselect failed
15:27:51: TTY4: Line reset
15:27:51: TTY4: Modem: READY->HANGUP
15:27:52: TTY4: dropping DTR, hanging up
15:27:52: tty4: Modem: HANGUP->IDLE
15:27:57: TTY4: restoring DTR
15:27:58: TTY4: DSR came up
The router continues to generate such output until you enter the corresponding no debug command (in
this case, the no debug modem command).
If you enable a debug command and no output is displayed, consider the following possibilities:
•
•

Redirecting debug and Error Message Output

By default, the network server sends the output from debug commands and system error messages to the
console. If you use this default, monitor debug output using a virtual terminal connection, rather than
the console port.
To redirect debug output, use the logging command options within configuration mode as described in
the following sections.
Possible destinations include the console, virtual terminals, internal buffer, and UNIX hosts running a
syslog server. The syslog format is compatible with 4.3 Berkeley Standard Distribution (BSD) UNIX
and its derivatives.
OL-18089-01, Cisco MDS NX-OS Release 4.x
The router may not be properly configured to generate the type of traffic you want to monitor. Use
the more system:running-config EXEC command to check its configuration.
Even if the router is properly configured, it may not generate the type of traffic you want to monitor
during the particular period that debugging is turned on. Depending on the protocol you are
debugging, you can use commands such as the TCP/IP ping EXEC command to generate network
traffic.
Cisco MDS 9000 Family Command Reference
Using Debug Commands
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