Re: [squid-users] Re: Per user bandwidth usage counting

From: Amos Jeffries <>
Date: Mon, 22 Apr 2013 01:30:38 +1200

On 21/04/2013 9:01 p.m., babajaga wrote:
> Amos,
> a bit off-topic, but anyway: How "transparent" is the "squid -k reconfigure"
> for the user ?

Depends on the changes that have been made to the config file and speed
of loading it.
Squid *pauses* the TCP accept and I/O handling while parsing the config
file. Then when configuration is all processed successfully it un-pauses
and keeps going.

Normally this whole process should be very fast and users only notice a
few hundred extra milliseconds of delay.

> Is squid simply refusing new connections, and waiting, until busy conns are
> finished, then doing the reconfig ?

No, squid is simply queueing all I/O events, new TCP connections and
packets pile up in the TCP buffers.

> When doing single-user test of my simple method, I did not notice any glitch
> during brwoser session, when the "reconfigure" was done. However, with many
> users, this might be different.

Yes you should not notice it unless there is a lot of traffic throughput
at the time or there are a lot of big changes to be done (ie loading MB
of a ACL blacklists every hour could be problematic).

Still the pause is a periodic impact on *all* traffic, however small.
Whereas using an external_acl_type helper to check things provides
real-time ACL changing and no queuing at all for any of the accept() or
I/O operations.

Received on Sun Apr 21 2013 - 13:30:54 MDT

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