This searches for and destroys the zombie processes that linger (and block I/O for an indefinite amount of time) after cron starts up on a shared server:
for each in `ps jauxww | grep Z | grep -v PID | awk '{print $3}'`; do for every in `ps auxw | grep $each | grep cron | awk '{print $2}'`; do kill -9 $every; done; done