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From Christian Gottschalch <ma...@llbc.de>
Subject Re: [users@httpd] mod_proxy maximum connections to a backend
Date Wed, 10 Jan 2007 14:41:04 GMT
have a look http://apache.ivn.cl/ may be interesting


George Barnett schrieb:
> Hmm,
>
> That makes sense to me, although it sounds like a great way to kill a 
> backend.  Given the thread limit per processes is 64, you'd end up 
> having almost no way of controlling connections to the backend.
>
> George
>
> Christian Gottschalch wrote:
>> Hi,
>>
>> i think it ist per process, so if you have 100 processes with max 
>> value 200 your Hard Maximum will be 20000 connections, but im not shure.
>>
>> Documentation says 
>> (http://httpd.apache.org/docs/2.2/mod/mod_proxy.html#proxypass):
>> The default for a Hard Maximum for the number of connections is the 
>> number of threads per process in the active MPM.
>>
>> which makes sense, because every thread can handle one request, to 
>> handle the request a minimum of one connection to the proxyed server 
>> is needed, therefore i think it must be a per process setting. In 
>> prefork mode it is set to 1, because  if you use prefork only one 
>> request can be handled per process.
>>
>> regards.
>>
>>
>> George Barnett schrieb:
>>> Hi All,
>>>
>>> I've asked this on irc and it was suggested that I try asking the dev
>>> because the docs aren't clear, but I'll ask here aswell.
>>>
>>> I'm using apache httpd 2.2.3 with the event MPM to do some traffic
>>> throttling to a backend.  What I have is this:
>>>
>>> First, traffic hit a default vhost with lots of rewrite rules such 
>>> as this:
>>>
>>> RewriteCond %{REQUEST_URI}    ^/page.*$ [NC]
>>> RewriteCond %{QUERY_STRING}   ^.*pattern.*$ [NC]
>>> RewriteRule ^(.*)$ http://trafficclass.localhost/$1 [P,L]
>>>
>>> In the hosts file, trafficclass.localhost is 127.0.0.1, so from 
>>> there, the
>>> traffic heads back into a vhost.
>>>
>>> Then I have a vhost with the following in it:
>>>
>>> <VirtualHost 127.0.0.1:80>
>>>  DocumentRoot /opt/apache/htdocs
>>>  ServerName trafficclass.localhost
>>>  ProxyRequests off
>>>  ProxyBadHeader Ignore
>>>
>>>  CustomLog /var/log/apache2/gold-access.log combined
>>>  Errorlog /var/log/apache2/gold-error.log
>>>
>>>  <Location />
>>>   ProxyPass http://1.2.3.4/ max=200 acquire=500
>>>   # IIS Sucks
>>>   SetEnv force-proxy-request-1.0 1
>>>   SetEnv proxy-nokeepalive 1
>>>  </Location>
>>> </Virtualhost>
>>>
>>> In my setup I have 100 processes with 64 threads per process.
>>>
>>> Last night during exceptional load, I saw over 3200 connections to the
>>> backend.  My question - is it possible that max=200 is a per process 
>>> and
>>> not server wide limit?
>>>
>>> If so, there's a way to set a server wide limit to the backend?
>>>
>>> Cheers,
>>>
>>> George
>>>
>>
>>
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>
>


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