How to set up serial console redirection
Serial console redirection is used to capture error messages that often scroll off the screen during a system crash. This is often required to debug the crash.
Serial console redirection requires a null modem cable and a 2nd system. First, connect a null modem cable between the target system and the 2nd system. On the target system, add the following kernel parameters to the boot loader (/etc/grub.conf):
console=ttyS0,38400 console=tty0
After making the change, reboot the target system.
On the 2nd system, use the minicom terminal emulator to capture the serial output. Minicom must first be configured with the same serial settings as the system being monitored:
# minicom -s
Select 'Serial port setup' and modify the following options to match:
- A - Serial device
- E - Bps/par/bits
Next, choose 'Save settings as dfl' and then exit the program.
Finally, start minicom without the -s flag:
# minicom
To make sure all critical kernel messages are captured, log the serial output to a file by pressing and releasing CTRL-A and then pressing L.
The example assumes thefirst serial port is used. To use the 2nd serial port, replace ttyS0 with ttyS1.