Re: Re: Apache server getting lot of Closing connection

[Igor Cicimov <icicimov@xxxxxxxxx>]

It's not very clear what are you saying. Please post some output from the netstat command.

I guess you are talking about the back end connections between apache and tomcat. What is the session time in your tomcat application? What are the timeout settings in the apache config including KeepAlive and KeepAliveTimeout settings (if any)? Check those and adjust according to your needs.

According to RFC793 the time wait can be as twice the Maximum
Segment Lifetime (MSL). MSL is specified to be 2 minutes. So, a socket
could be in a TIME_WAIT state for as long as 4 minutes. So check your tcp kernel settings for the sockets too. This command "ndd /dev/tcp \?" should give you all the parameters so have a look and tune them if necessary.

Basically if you see lots of CLOSE_WAIT sockets on the apache towards the tomcat that means the app has sent FIN request to close the connection but the apache is still holding it open. So I would look at the apache timeouts and the linux tcp kernel settings to correct this.

Hope this helps.

Igor

On Mon, Feb 15, 2010 at 2:58 AM, Arunkumar Janarthanan <arunkumar.webadmin@xxxxxxxxx> wrote:

Could anyone please advice on this ?

On Sat, Feb 13, 2010 at 10:26 PM, Arunkumar Janarthanan <arunkumar.webadmin@xxxxxxxxx> wrote:

Hi,

I have Apache server 2.2.6 running on RedHat Linux 5 with ProxyPass and Reverse Proxy configured. The server limit has 512 connections.

Now that the number of connection has always Closing connection and when load increases they make the maximum connection reached out. I used netstat -a output to check what is causing this could not much understand if this is caused by TIME_WAIT or the connections established to Tomcat not getting released.

Please advice.

./apachectl_rd -V
Server version: Apache/2.2.6 (Unix)
Server built:   Sep 26 2007 11:18:50
Server's Module Magic Number: 20051115:5
Server loaded:  APR 1.2.11, APR-Util 1.2.10
Compiled using: APR 1.2.11, APR-Util 1.2.10
Architecture:   32-bit
Server MPM:     Prefork
  threaded:     no
    forked:     yes (variable process count)


./apachectl_rd -D DUMP_MODULES
Loaded Modules:
 core_module (static)
 authn_file_module (static)
 authn_default_module (static)
 authz_host_module (static)
 authz_groupfile_module (static)
 authz_user_module (static)
 authz_default_module (static)
 auth_basic_module (static)
 include_module (static)
 filter_module (static)
 log_config_module (static)
 env_module (static)
 setenvif_module (static)
 proxy_module (static)
 proxy_connect_module (static)
 proxy_ftp_module (static)
 proxy_http_module (static)
 proxy_ajp_module (static)
 proxy_balancer_module (static)
 ssl_module (static)
 mpm_prefork_module (static)
 http_module (static)
 mime_module (static)
 status_module (static)
 autoindex_module (static)
 asis_module (static)
 cgi_module (static)
 negotiation_module (static)
 dir_module (static)
 actions_module (static)
 userdir_module (static)
 alias_module (static)
 rewrite_module (static)
 so_module (static)
 deflate_module (shared)
 php5_module (shared)
 remoteip_module (shared)
Syntax OK