As on many systems init scripts and the handling of services is based on pid files I extended the mtt-relay script as follows:
If run with the --daemon option
* Create file /var/run/mtt-relay.pid if it does not exist and write the pid of the background process into it.
* exit with return value 1 if /var/run/mtt-relay.pid file exists.
Patch is attached.
High Performance Computing Center Stuttgart (HLRS)