[hobbit] performance tuning

[ZanDAhaR]

Henrik Stoerner wrote:
> On Tue, Apr 04, 2006 at 06:11:57PM -0500, Jeff Newman wrote:
>   
>> I'm running Hobbit 4.1.2p1 on a Redhat AS 4 server.
>>
>> I currently have a number of server side scripts that post-process
>> incoming test results.
>>
>> My concern is a high number of "1984" sockets in TIME_WAIT condition
>> (upwords of 60 on the client at times) The clients are AIX boxes.
>>     
>
> I dont really understand why you see so many TIME_WAIT connections on
> the *client*. I could understand if they were on the Hobbit server, but
> not on the client...
>
> If there is a firewall between the clients and the server, it could be
> that the firewall terminates the connection tracking state before the
> final exchange of FIN/ACK packets has completed between the two sides.
> But then I'd expect it to be in FIN_WAIT_[1,2] ...
>
> What's TIME_WAIT anyway ... from
> http://www.ssfnet.org/Exchange/tcp/tcpTutorialNotes.html:
>
>   "The main thing to recognize about connection teardown is that a
>    connection in the TIME_WAIT state cannot move to the CLOSED state until
>    it has waited for two times the maximum amount of time an IP datagram
>    might live in the Inter net. The reason for this is that while the local
>    side of the connection has sent an ACK in response to the other side's
>    FIN segment, it does not know that the ACK was successfully delivered.
>    As a consequence this other side might re transmit its FIN segment, and
>    this second FIN segment might be delayed in the network. If the
>    connection were allowed to move directly to the CLOSED state, then
>    another pair of application processes might come along and open the same
>    connection, and the delayed FIN segment from the earlier incarnation of
>    the connection would immediately initiate the termination of the later
>    incarnation of that connection."
>
> So TIME_WAIT states should only stay around for a few minutes - I
> believe a common "2 x max lifetime" is 2 minutes, but this is somewhat
> OS dependant. Since the Hobbit client only runs once every 5 minutes,
> I don't understand why you have many of these on the clients.
>
>
> Henrik
>
>
>
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>
>   
I just checked a number of hosts here and none of them had anything like 
this. About the most I saw was 6 time waits all of which only hung 
around for 60 secs maybe 90 tops. Even on both our servers we dont have 
any time waits on the hobbit port, only from the client that sends it 
stats to the other server but same again minute tops.

Id suggest the same as what Henrik already has so I won't say any more

Allan

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