@jussy - I think you want to look at this: http://docs.python.org/2/c-api/init.html#threads You want to wrap the copy job invocation with Py_BEGIN_ALLOW_THREADS / Py_END_ALLOW_THREADS. Otherwise, FileSystem.copy() holds the global interpreter lock and no other python threads can run. --- Reply to this email directly or view it on GitHub: https://github.com/xrootd/xrootd-python/issues/8#issuecomment-34024219 ######################################################################## Use REPLY-ALL to reply to list To unsubscribe from the XROOTD-DEV list, click the following link: https://listserv.slac.stanford.edu/cgi-bin/wa?SUBED1=XROOTD-DEV&A=1