[Linux-HA] cat < /dev/ttyS0 gives no output

[Christof Amelunxen]

Hi,

Am Di, den 26.07.2005 schrieb Anquijix Schiptara um 15:16:
> >Did you test this while heartbeat is running? I suppose that wont work
> >because the messages on ttyS0 are intercepted by the heartbeat process.
> 
> I though, heartbeat locks the serial interface, so i stopped it and tried it 
> again... same problem.

You should recieve the heartbeat messages from one node if you listen on
ttyS0 on the other node while heartbeat is stopped there. So you dont
recieve them at all?

> >...that basically is exactly what heartbeat is supposed to do: listening
> >for heartbeat messages and react if there are none. Why would you monitor
> >it separately?!?

> But in general, i only want to be informed, that something doesnt work 
> anymore with the serial interface.
> If i break the serial connection without breaking the eth1 connection, i 
> only have a log entri in ha-log, that says TTY write timeout or somthing 
> like that.  Thats a good hint of heartbeat, but i dont want to grep after 
> TTY timeouts in the log, so i decided to monitor the serial interface, that 
> i receive a mail, if the connection breaks.

The log says "Link nodename:/dev/ttyS0 dead" if the serial link is down.
But you can query the status of your heartbeat links with cl_status
pretty easily, no need to monitor the logs for that purpose.

regards,
Christof