Hi,
We have been using Apache Proxy Server and we have noticed some strange
behavior w.r.t network usage.
The network usage of Apache Proxy server and the client machine which is
connected to it are being monitored. A download
(http://ftp.surfnet.nl/ftp/pub/os/Linux/distr/fedora/1/i386/iso/) have been
initiated from the client machine. Before the download gets completed, it is
cancelled from the client.
It is noticed that the network usage of Apache Proxy Server is still high,
even if the download gets cancelled and it remains high for considerable time(
the time equivalent for the entire download to complete).
What are the reasons for this behavior?
To ascertain the fact that Proxy server still process the download, when it is
cancelled from client, we did few more tests with only one client connected to
Apache Proxy.
1. Download initiated from client, cancelled it after 20 minutes. The after 20
minutes, the Apache Proxy Server is stopped.
It is noticed that as soon as download is initiated, the network bandwidth
usage (transmit bps ) by Apache Proxy Server goes high ( almost 0.8 Mbps ).
When the download is cancelled from client, the transmit bps of Apache proxy
serve remains same.
Only when Apache is stopped, the transmit bps comes down (obvious). In one of
the tests, Apache was not stopped, and monitored the transmit bps, which has
remained high for the time equivalent to complete download time.
2. Two proxy servers were used in the second test, where the client is
connected to first Apache Proxy Server, which is connected to Second Proxy
Server.
The download is initiated from client, cancelled it from client, then First
Apache Proxy Server is stopped and Finally Second Apache Proxy Server is
stopped.
When the download is cancelled, the transmit bps of both the First Apache
Proxy and Second Apache Proxy remains high. Even if the First Proxy Server is
stopped, the transmit bps of Second Proxy Server remains high.
3. Different versions of Apache have been tried.
The same behavior is exhibited with httpd 2.0.48, 2.0.50 and 2.2.0.
We would like to know why is such behavior being exhibited by Apache Proxy.
In case, more information is required, I can send more details.
Regards,
Saleem
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