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From Brian Geffon <bri...@apache.org>
Subject Re: Reverse proxy and large HTTP requests
Date Fri, 05 Sep 2014 23:08:04 GMT
You might try setting proxy.config.http.server_tcp_init_cwnd to something
like 10.

Brian


On Fri, Sep 5, 2014 at 3:51 PM, Fabien Duranti <fduranti@ymail.com> wrote:

>  Hello,
>
> I am running a proof of concept with ATS 4.2.2 in reverse proxy mode to
> improve user experience when accessing a web application over an high
> latency link ( 255ms RTT )
>
> The setup is the following :
>
> client -> ATS1 --- High latency link --- > ATS2 -> origin_server
>
> all connections have SSL.
>
> Everything behaves as expected when client requests are small, response
> times when connections are established pretty much correspond to RTT +
> origin response time + the negligible ATS processing time.
> However, when requests are bigger than something around 3000bytes (POSTs
> typically), reponse times are  looking more like 2x RTT + origin response
> time.
> Running a network capture showed that when ATS1 sends a big request, there
> are on the wire 2x 1500bytes packets sent, then wait for ATS2's ACK, then
> another small packet to send the remaining of the request. That wait for
> the ACK pretty much makes response times mutltipled by 2.
> I immediately thought about the TCP tunning of the operating system
> (RHEL6) could be wrong but running the exact same request with curl on ATS1
> wouldn't show that. on the wire we would rather see two fragmented packets
> of 2650bytes + 800bytes and the response from ATS 2 comming shortly after
> the RTT.
>
> Is there any misconfiguration in ATS that would explain this ? I tried
> proxy.config.ssl.max_record_size  = 0 then 1000, then 4000 but didn't see
> any difference
>
> Thanks !
>
> --
> Fabien Duranti
>

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