How to deal with error: Too many open files in system?

Question

I am running a cron and output coming to my id and getting below as output:

/bin/sh: /usr/bin/php: Too many open files in system

Cron runs every 5 mins.

Have checked /var/logs/cron and cron is executed every 5 mins.

Sites are working fine on the server.

Solution

This means your system ran out of file handles, either in your php or in another application. Make sure to close any files you open to free file handles.

To the number of handles of every program running, use (as root):

for p in $(ps -A -o pid); do
    nh=$(ls /proc/$p/fd  2>/dev/null | wc -l) &&
    exe=$(readlink -f /proc/$p/exe  2>/dev/null) &&
    echo "$p ($exe): $nh"
done

For a more verbose output, use lsof.

You can also increase the number of possible system file handles by modyfing /etc/security/limits.conf (which effects changes to /proc/sys/fs/file-max), and decrease it for the current terminal session with ulimit -n.

Comments

[dogbane]

+1 In addition might be open processes. See docs.php.net/pclose

[phihag]

@fyr Clarified. Is the new version accurate?

[fyr]

@phihag: yes i removed also my post to keep the answers less redundant

[phihag]

@fyr Your answer was actually quite good, and I see no detriment in having multiple answers focus on different parts of the solution. Incorporated some good parts.

[Admin]

When I checked messages log I found, ALERT - script tried to increase memory_limit to 268435456 bytes which is above the allowed value and script name,I checked memory_limit =256 MB in php.ini

[Douglas Gaskell]

Would be great if this sorted by the number of open files.