diag "$BT_TESTS_PYTHON_BIN $server_script --port-file $port_file --trace-path-prefix $trace_dir_native $server_args"
echo "$server_args" | run_python xargs "$BT_TESTS_PYTHON_BIN" "$server_script" \
--port-file "$port_file" \
- --trace-path-prefix "$trace_dir_native" &
+ --trace-path-prefix "$trace_dir_native" 1>&2 &
# write PID to file
echo $! > "$pid_file"