Re: [SQU] half_closed_clients on/off ?

Pat Newby wrote:

> [ Squid 2.2.STABLE4 on a SUN Ultra, Solaris 2.6 ]
>
> In squid.conf, the default is:
> half_closed_clients on
>
> Will squid display certain symptoms to indicate if this should be
> turned off ? If so, what should I look for ?

With Solaris? Look at the number of connections in CLOSE_WAIT. If
the CLOSE_WAITs on your server are inacceptably high, e.g.

        netstat -anf inet | fgrep CLOSE_WAIT | wc -l

is > 100 (this varies from system to system), Squid performance
degrades for reasons beyond me, and you should definitely try to
turn half_close_clients off. In my experience, the problem goes
away, if there are only very few half closed clients.

Apart from this, having a TCP connection in CLOSE_WAIT at one
side, and FIN_WAIT_2 on the other side is perfectly legal for
unidirectional payload data transfers, so CLOSE_WAIT is *not*
evil per se (Stevens, TCPIPIv1, chapter 18ff).

-- 
Le deagh dhùrachd,
Dipl.-Ing. Jens-S. Vöckler (voeckler@rvs.uni-hannover.de)
Institute for Computer Networks and Distributed Systems
University of Hanover, Germany; +49 511 762 4726
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