[users@httpd] Some questions regarding Apache HTTP Server ServerLimit (Too Many Child Processes)

[갈준영 <jy...@mz.co.kr>]

Hello,

I'm using Apache HTTP Server 2.2.32 on Linux.

I see that too many child processes are being made on Apache HTTP Server.

Child processes are being made up to 256 on Apache HTTP Server.

Apache HTTP Server is using ServerLimit default value(256).

Q. Could you please provide me how to set ServerLimit value greater than
ServerLimit default value(256) on Apache HTTP Server?

Q. Could you please give me any advice for reducing be being made too many
child processes on Apache HTTP Server?

Q. Is tcpdump helpful for analyzing why the issue has been happening?
I thought tcpdump wouldn't be helpful to analyze why the issue has been
happening.

Please refer the following information.

Server version: Apache/2.2.32 (Unix)
Server built:   Nov 10 2017 14:18:57
Server's Module Magic Number: 20051115:42
Server loaded:  APR 1.5.2, APR-Util 1.5.4
Compiled using: APR 1.5.2, APR-Util 1.5.4
Architecture:   64-bit
Server MPM:     Prefork
  threaded:     no
    forked:     yes (variable process count)
Server compiled with....
 -D APACHE_MPM_DIR="server/mpm/prefork"
 -D APR_HAS_SENDFILE
 -D APR_HAS_MMAP
 -D APR_HAVE_IPV6 (IPv4-mapped addresses enabled)
 -D APR_USE_SYSVSEM_SERIALIZE
 -D APR_USE_PTHREAD_SERIALIZE
 -D SINGLE_LISTEN_UNSERIALIZED_ACCEPT
 -D APR_HAS_OTHER_CHILD
 -D AP_HAVE_RELIABLE_PIPED_LOGS
 -D DYNAMIC_MODULE_LIMIT=128
 -D HTTPD_ROOT="/apps/apache"
 -D SUEXEC_BIN="/apps/apache/bin/suexec"
 -D DEFAULT_PIDLOG="logs/httpd.pid"
 -D DEFAULT_SCOREBOARD="logs/apache_runtime_status"
 -D DEFAULT_LOCKFILE="logs/accept.lock"
 -D DEFAULT_ERRORLOG="logs/error_log"
 -D AP_TYPES_CONFIG_FILE="conf/mime.types"
 -D SERVER_CONFIG_FILE="conf/httpd.conf"

ServerLimit 256
Timeout 1800

<IfModule mpm_prefork_module>
    StartServers         32
    MinSpareServers      25
    MaxSpareServers      75
    MaxClients         1024
    MaxRequestsPerChild   0
</IfModule>

Thanks in advance.

Thanks,

Mohammed G.

Re: [users@httpd] Some questions regarding Apache HTTP Server ServerLimit (Too Many Child Processes)

[Richard <li...@listmail.innovate.net>]

> Date: Friday, May 18, 2018 14:59:21 +0900
> From: <jy...@mz.co.kr>

> Hello,
> 
> I'm using Apache HTTP Server 2.2.32 on Linux.
> 
> I see that too many child processes are being made on Apache HTTP
> Server.
> 
> Child processes are being made up to 256 on Apache HTTP Server.
> 
> Apache HTTP Server is using ServerLimit default value(256).
> 
> Q. Could you please provide me how to set ServerLimit value greater
> than ServerLimit default value(256) on Apache HTTP Server?
> 
> Q. Could you please give me any advice for reducing be being made
> too many child processes on Apache HTTP Server?
> 
> Q. Is tcpdump helpful for analyzing why the issue has been
> happening? I thought tcpdump wouldn't be helpful to analyze why the
> issue has been happening.
> 
> Please refer the following information.
> 
> 
> ServerLimit 256
> Timeout 1800
> 
> <IfModule mpm_prefork_module>
>     StartServers         32
>     MinSpareServers      25
>     MaxSpareServers      75
>     MaxClients         1024
>     MaxRequestsPerChild   0
> </IfModule>
> 
> 
> Mohammed G.

You can increase your server limit above the 256 default by changing
the value on that line in your config file (and restarting your
server). Increasing your server limit value is just addressing the
symptom not the underlying problem. That you have your Timeout set
abnormally high is not helping the issue.

While it could be that your server is just under resourced for the
amount of use it is getting, generally you hit server/maxclient
limits when some content/resource on your site takes a long time to
process and/or be sent to the client. Do an analysis of your server
logs, checking for slow serving times.



---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@httpd.apache.org
For additional commands, e-mail: users-help@httpd.apache.org