Is there any specific reason that you need to run them all at the same time? I imagine that you are worried about system resources, but I can't imagine that your network would be much happier. Why not try a linear execution embedded with forks (i.e. limiting your processes to 10 or so at a time while going through the list.) You might need to experiment which number of processes makes the least intrusive use of system resources and network since both are probably doing more important things in the meantime.