Ubuntu – Squid running out of file descriptors on Ubuntu

I am running Squid 2.7 on Ubuntu 10.04 64bits.
I had the problem of Squid running out of file descriptors, with the following error showing in /var/log/squid/cache.log:

WARNING! Your cache is running out of filedescriptors

I checked with:

squidclient mgr:info | grep 'file descri'

and it showed that I had only 1024 file descriptors available.

I changed /etc/security/limits.conf, adding this at the end:

* soft nofile 32768
* hard nofile 32768
proxy           soft    nofile          32768
proxy           hard    nofile          32768

Added this to /etc/squid/squid.conf:

max_filedescriptors 32768

Also changed /etc/default/squid:

SQUID_MAXFD=32768

Nothing was working out. In the end I edited /etc/init.d/squid to add "ulimit -n 32768":

#!/bin/sh -e
# upstart-job
#
# Symlink target for initscripts that have been converted to Upstart.

set -e
ulimit -n 32768
<... snipped  ...>

That worked! 🙂

I had to do all this under the stress of a live, production Squid server being incredibly slow, so I am sure that this is NOT the right way to do it.

But what is the right way to do it?