How to track down a file descriptor leak

lsofmax-file-descriptors

I have a java process (Glassfish) which is leaking file descriptors. I know this because I get the helpful java.io.IOException: Too many open files exception. I can look in /proc/PID#/fd and see all the open file descriptors. When I use lsof I get a very large number of entries like this:

java 18510 root 8811u sock 0,4 1576079 can't identify protocol
java 18510 root 8812u sock 0,4 1576111 can't identify protocol
java 18510 root 8813u sock 0,4 1576150 can't identify protocol

I see 12 new ones created per minute. What options can I use on lsof or what other tools are available to me to help track down socket file descriptors where the protocol can't be identified?

Best Answer

to see the top 20 file handle using processes:

for x in `ps -eF| awk '{ print $2 }'`;do echo `ls /proc/$x/fd 2> /dev/null | wc -l` $x `cat /proc/$x/cmdline 2> /dev/null`;done | sort -n -r | head -n 20

the output is in the format file handle count, pid, cmndline for process

example output

701 1216 /sbin/rsyslogd-n-c5
169 11835 postgres: spaceuser spaceschema [local] idle
164 13621 postgres: spaceuser spaceschema [local] idle
161 13622 postgres: spaceuser spaceschema [local] idle
161 13618 postgres: spaceuser spaceschema [local] idle
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