...$ python
Python 3.6.0 |Anaconda 4.3.0 (64-bit)| (default, Dec 23 2016, 12:22:00) 
[GCC 4.4.7 20120313 (Red Hat 4.4.7-1)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from multiprocessing import Pool
>>> p = Pool(1)
>>> p.close()
>>> p.join()
>>> p = Pool(500)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/memex/vyf/anaconda3/lib/python3.6/multiprocessing/context.py", line 119, in Pool
    context=self.get_context())
  File "/memex/vyf/anaconda3/lib/python3.6/multiprocessing/pool.py", line 168, in __init__
    self._repopulate_pool()
  File "/memex/vyf/anaconda3/lib/python3.6/multiprocessing/pool.py", line 233, in _repopulate_pool
    w.start()
  File "/memex/vyf/anaconda3/lib/python3.6/multiprocessing/process.py", line 105, in start
    self._popen = self._Popen(self)
  File "/memex/vyf/anaconda3/lib/python3.6/multiprocessing/context.py", line 277, in _Popen
    return Popen(process_obj)
  File "/memex/vyf/anaconda3/lib/python3.6/multiprocessing/popen_fork.py", line 20, in __init__
    self._launch(process_obj)
  File "/memex/vyf/anaconda3/lib/python3.6/multiprocessing/popen_fork.py", line 67, in _launch
    self.pid = os.fork()
BlockingIOError: [Errno 11] Resource temporarily unavailable
>>> p = Pool(1)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/memex/vyf/anaconda3/lib/python3.6/multiprocessing/context.py", line 119, in Pool
    context=self.get_context())
  File "/memex/vyf/anaconda3/lib/python3.6/multiprocessing/pool.py", line 168, in __init__
    self._repopulate_pool()
  File "/memex/vyf/anaconda3/lib/python3.6/multiprocessing/pool.py", line 233, in _repopulate_pool
    w.start()
  File "/memex/vyf/anaconda3/lib/python3.6/multiprocessing/process.py", line 105, in start
    self._popen = self._Popen(self)
  File "/memex/vyf/anaconda3/lib/python3.6/multiprocessing/context.py", line 277, in _Popen
    return Popen(process_obj)
  File "/memex/vyf/anaconda3/lib/python3.6/multiprocessing/popen_fork.py", line 20, in __init__
    self._launch(process_obj)
  File "/memex/vyf/anaconda3/lib/python3.6/multiprocessing/popen_fork.py", line 67, in _launch
    self.pid = os.fork()
BlockingIOError: [Errno 11] Resource temporarily unavailable
>>>