httpd and default instances of apache

devUnix · 07-29-2013, 05:01 AM

Hi,

Sideline (you can skip this): It seems after working for over 1 year in a Telecom company and providing support for applications, I have almost forgotten Linux Servers Administration related stuffs.

Does the following output mean there are 8 instances of apache available on the system?

Code:

[root@Dev ~]# ps aufx | grep -i [h]ttpd
root     30147  0.0  0.6 351616 25920 ?        Ss   Jan17   0:11 /usr/sbin/httpd
apache    1598  0.0  0.6 364292 24440 ?        S    Jul28   0:00  \_ /usr/sbin/httpd
apache    1599  0.0  0.4 351616 19436 ?        S    Jul28   0:00  \_ /usr/sbin/httpd
apache    1600  0.0  0.6 364292 24588 ?        S    Jul28   0:00  \_ /usr/sbin/httpd
apache    1626  0.0  0.6 368408 27200 ?        S    Jul28   0:00  \_ /usr/sbin/httpd
apache    1627  0.0  0.6 364292 24732 ?        S    Jul28   0:00  \_ /usr/sbin/httpd
apache    1628  0.0  0.6 364292 24656 ?        S    Jul28   0:00  \_ /usr/sbin/httpd
apache    1629  0.0  0.6 366360 25068 ?        S    Jul28   0:00  \_ /usr/sbin/httpd
apache    1630  0.0  0.6 368408 26200 ?        S    Jul28   0:00  \_ /usr/sbin/httpd

For httpd, the count is: 9.

What I understand is when we run httpd it forks 8 instances of httpd and calls them apache. These 8 instances are there to load-balance requests from clients/browsers. Is this correct?

How can we have more instances of apache instead of the default 8 above? Can I have 16 or more when I start httpd?

Please help me understand the above stuff.

Thanks,
Dev.

bathory · 07-29-2013, 05:42 AM

Quote:

What I understand is when we run httpd it forks 8 instances of httpd and calls them apache.

It starts the 8 child processes as the user apache

Quote:

These 8 instances are there to load-balance requests from clients/browsers. Is this correct?

No, each one is used to serve a request

Quote:

How can we have more instances of apache instead of the default 8 above? Can I have 16 or more when I start httpd?

Sure, use in httpd.conf

Code:

StartServers 16

See this for more options

Regards

SAbhi · 07-29-2013, 11:14 PM

You can verify what Bathory said by :

Code:

ps -p [pid] -o ppid=      # this will output the Parent process id of the running child pid.

That will make the concept clear.

devUnix · 07-30-2013, 12:07 AM

Thanks to Sabhi and Bathory!