Re: [squid-users] [reverse proxy] ESTABLISHED on squid server

On 22/06/11 22:54, Le Trung, Kien wrote:
> Hi, I trouble about how to reduce the ESTABLISHED statuses of connections.
> It always have approximately 6300 ESTABLISHED connections when server
> at high load time of the day and just reduce below 1000 ESTABLISHED in
> the midnight.
>
> 1 established)
> 1 Foreign
> 5 FIN_WAIT2
> 6 LISTEN
> 11 CLOSING
> 43 SYN_RECV
> 63 LAST_ACK
> 237 FIN_WAIT1
> 1331 TIME_WAIT
> 6258 ESTABLISHED
>
> I wonder how to free the connection after data all been tranferred
> between squid server and clients. (I think squid keeps connections as
> much as possible).

Depends on which Squid you have. 3.1 and later try to use HTTP/1.1
features to speed up client access times. These require persistent
connections.

~6300 connections is not bad. Your box can handle far more than that easily.

> On another web server (same operating system and hardware, etc ...)
> which has the same connections to (because of DNS round-robin) the
> ESTABLISH connections are range from 2000-3000.

This is not a valid comparison. see:
http://wiki.squid-cache.org/Features/LoadBalance#Bias:_Connection-based

This same problem affects DNS round-robin and TCP SYN load balancers.
Which are also per-connection.

Generally speaking ESTABLISHED is good. They are either currently in
active use or waiting and will have zero TCP connection setup delay when
they are needed.

The more recent your Squid version number the more efficiently it
handles persistent connections. Thus the lower number it uses. So if
this is actually a problem for you a newer version is better.

You can also adjust it by tweaking the idle_timeout directive. Which
determines a maximum amount of time any one connection can be kept waiting.

You can disable the persistence and all HTTP features which rely on it
by configuring client_persistent_connections and/or
server_persistent_connections OFF.

Amos

-- 
Please be using
   Current Stable Squid 2.7.STABLE9 or 3.1.12
   Beta testers wanted for 3.2.0.9 and 3.1.12.3