Re: Understanding the APACHE 1.3 process model

Michael Conlen <m@xxxxxxxxxx> · Fri, 28 Sep 2007 09:02:14 -0400

During a time when system resources are limited such as a DoS or even  

just an app run amok I've found SNMP to be a pretty good way to get  

information on the system. With net-snmp you can walk the tree to  

find connection information. Net-snmp will likely have issues if you  

try to walk the whole tree and you need to use a proper timeout but  

it's much less resource intensive because it avoids forking, which  

anyone who's logged in to a system without memory can tell you takes  

*forever*.

--
Michael Conlen

On Sep 28, 2007, at 2:43 AM, Christian Folini wrote:

On Fri, Sep 28, 2007 at 01:13:44PM +1000, Robinson Craig wrote:

Therefore, this makes me think that I can't actually use netstat to

'measure' the 'number of concurrently connected clients'? Is this  

a fair

assumption?

Hey Craig,

You can still do that, but limit yourself to the Established
connections. It gives you the advantage to be independent of
apache in case of a DoS when mod_status is unavailable.

For all other purposes, the latter is the better option,
as it gives you more information. See Michael's message.

cheer,

Christian

Cheers, Craig

-----Original Message-----
From: Sander Temme [mailto:sctemme@xxxxxxxxxx]
Sent: Friday, 28 September 2007 1:01 PM
To: users@xxxxxxxxxxxxxxxx
Subject: Re:  Understanding the APACHE 1.3 process model

On Sep 27, 2007, at 7:51 PM, Michael Conlen wrote:

you likely have 23 established connections using server processes  

and

an additional number of server processes available to handle new
connections. Apache keeps some number of processes available so that
it doesn't have to fork the process at the time the request is made,
but instead has the process ready to go. There are httpd.conf
parameters to specify the minimum and maximum of these to keep
available.

See MinSpareServers, MaxSpareServers.

The TIME_WAIT, FIN_WAIT_1, FIN_WAIT_2 and LAST_ACK sockets should  

not be

attached to httpd children.

httpd doesn't deal with the TCP layer, it deals with socket file
descriptors.

S.

--
Sander Temme
sctemme@xxxxxxxxxx
PGP FP: 51B4 8727 466A 0BC3 69F4  B7B8 B2BE BC40 1529 24AF

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