Hi,
I have 2 servers connected together via a serial console, each server has just one serial port (com1 port). So there is just the one serial link between the servers (via null modem cable).

Lets call them server A and server B. If server B is having a problem I would like to be able to connect to server B via serial console from server A. If server A was to have a problem I would like to be able to connect to server A from server B over serial console.

So I have configured both servers to enable a serial console, via adding serial console setup lines in /boot/grub/grub.conf and /etc/inittab . What I have found is that when both servers have serial console enabled I cannot login to either server, from the other server. I can only have one server setup with serial console and the other needs to have no serial console setup (no entries in /boot/grub/grub.conf /etc/inittab). Only in this server / client setup will it work.

This is a pain because it means if I want to connect to server B from server A over serial console I have to first edit /boot/grub/grub.conf and /etc/inittab on server A (to turn off its serial console) and then reboot server A. Then I can connect to server B over serial console from server A. After doing my work over the serial console I then need to again edit /boot/grub/grub.conf and /etc/inittab on server A (to turn serial console on again) and reboot server A again.

I need both servers to be in this serial console enabled state by default because I will never know which one will crash first. So this means each time there's a problem and I need to use a serial console I will be forcing 2 reboots on the other server which is running fine. In a high uptime environment that's not ideal.

Is there anyway I can disable a serial console without having to edit grub.conf and inittab and reboot the server? I'm looking for some simple way of temporarily turning one of the servers serial consoles off and then turning it back on again after I'm done, without the reboots.

Can anyone help?

If you don't think this is possible please post and say so. I can live with rebooting if I have to - I'm not sure if what I'm asking is even possible? I would like to know if I'm wasting my time trying to do this, should I just accept rebooting and move on? Thanks.

I do not think it is possible.
Obviously other options would be to use another computer/laptop as a console device or maybe install another serial port on each server.