I am running carbon-cache.py and carbon-aggregator.py using daemon tools. When I made some changes in the storage-schema.conf and tried to restart the carbon-cache.py, I found that it is becoming zombie very frequently.

root      3367  3366  0 03:23 pts/1    00:00:00 supervise carbon-aggregator
root      3371  3366  0 03:23 pts/1    00:00:00 supervise carbon-cache
root      3373  3367  3 03:23 pts/1    00:00:02 /usr/bin/python /usr/bin/carbon-aggregator.py --debug start
root      3379  3372  0 03:23 pts/1    00:00:00 multilog t /var/log/multilog/carbon-cache
root      3382  3368  0 03:23 pts/1    00:00:00 multilog t /var/log/multilog/carbon-aggregator
root      3638  3371 21 03:24 pts/1    00:00:00 [carbon-cache.py] <defunct>

Can someone tell me what may be the reason ?