I use these commands to change the amount of file descriptors for squid. I have the commands added to the /etc/init.d/squid file. I added them right after the start command in this file. The commands I use are:
echo 65526 > /proc/sys/fs/file-max
ulimit -HSn 65536
If you are using them for smb, add the commands into the smbd init file.
hope this helps & good luck
Marco