squid max file descriptor – problem and fix

Symptoms:
Squid (2.6) stops responding when the number of connections reaches a certain number.

More symptoms:
A lot of lines like below start to appear in /var/log/squid/cache.log
WARNING! Your cache is running out of filedescriptors

Reason:
The default max file descriptor is set to 1024 in squid, which can be verified with
/usr/sbin/squidclient -h squid_host_or_ip -p squid_port mgr:info | grep descrip
or
/usr/sbin/squidclient mgr:info | grep descrip
if squid runs on localhost and default port.

The fix:
http://blog.nazmi.web.id/2007/06/20/squid-warning-your-cache-is-running-out-of-filedescriptors/comment-page-1/#comment-2828
http://paulgoscicki.com/archives/2007/01/squid-warning-your-cache-is-running-out-of-filedescriptors/

Os tested:
Centos