Re: Re: large amount of R in server-status

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2010/3/12 Hendrik Schmieder <hendrik.schmieder@xxxxxxxxx>
Dietmar Müller schrieb:

 Hi,

 I use since long time the apache in version 2.0 on windows 2000 (SP4).
 Since 4 weeks I can see (some times per day) many R in server-status.
 Sometimes so much that the server run full and stop working because all

 threads are used. I search in web and generally the response is that it have
 to do with dos but I'm not sure (or can't believe that)

 When I watch over some time the serverstatus I can see sometimes requests

 staying in R status until the configparameter timeout=300 (default) kick the
 request out. Sometimes this R staying requests use more then 50% from my
 reads and then after timeout all works like expexcted. Sometimes the

 complete webserver is blocked.

 Current I have 450 threads on apache and in background 2 clustered tomcats
 with a 200 threads.

 Can anybody explain me how it is possible that some (?) can send a rq to a

 webserver and don't finish the rq that the server wait for it? How can I
 solve such situations?

 Further: how can I identify and/or analyze a problem like this. I have now a
 situation where I have log the network trafik with wireshark.


 This problem start (about) at a time when we switch to a new provider.

 I have now version 2.0.57 but I have the problem also in the latest version
 from the 2.0 tree.

 If someone has some hint and or experience how to identify the problem -->

 thanks for any comment / hint

 regards Dietmar

Hi,
I found the problem :-)

http://ha.ckers.org/slowloris

/* for the archive */
to isolate the problem I write a small script which store every sec netstat -na

and the after analyze it and search some hours in web I found the problem.

Might after migration to an other os follow mod is a solution:
http://mod-qos.sourceforge.net/


hope this help other people!

If someone have any input about this pls let me know

regards Dietmar


And what is the root of your problem ?

regards

 Hendrik


The root problem is, that the apache webserver is susceptible for a small perl script what send incomplete / slow http requests and this cause that all threads from the httpd are in reading state.

Dietmar




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