Hello all my first time posting , so please be gentile. :)
We have 5 Apache 2.2.3 web servers behind a HAproxy load balancer. Each web server is a Quad core Xeon E5405@xxxxxxx with 16 gigs RAM and a hardware RAID 1 of 300 gigs
Apache is configure in prefork mode, as per Centos 5.5 install
We have recently had a 30% increase in traffic and will be expecting more. I would like to know the correct way to calculate the proper settings for prefork.c my settings, here is what I have now...
<IfModule prefork.c>
StartServers 150
MinSpareServers 125
MaxSpareServers 250
ServerLimit 600
MaxClients 600
MaxRequestsPerChild 1500
</IfModule>
I use to have these setting even higher, but when i calculated how much the server limit and max clients are giving that i have 16 gigs minus our memcache settings and some OS stuff it leaves me with about 9 gigs of RAM left that would calculate to about 382 as the max clients setting...
I am going to add more RAM today to make a total of 24 gigs on each server, and i am going to add an additional web server in the next week or so...
Each day we get about 5 million visits...
The only stats i have is that when the server gets a high load i grab a snapshot of the Apache processes running and the free mem, so it looks like this..
This is from yesterday(not sure why that defunt is there)
----------------
top - 15:30:03 up 3 days, 22:10, 3 users, load average: 9.24, 5.73, 5.27
Tasks: 365 total, 1 running, 363 sleeping, 0 stopped, 1 zombie
Cpu(s): 20.6%us, 5.6%sy, 0.0%ni, 71.0%id, 0.2%wa, 0.3%hi, 2.3%si, 0.0%st
Mem: 16435540k total, 4996748k used, 11438792k free, 624820k buffers
Swap: 2096472k total, 0k used, 2096472k free, 1907644k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
3352 root 15 0 479m 354m 524 S 7.8 2.2 200:22.25 memcached
21064 apache 15 0 0 0 0 Z 5.8 0.0 0:23.09 httpd <defunct>
21162 apache 15 0 414m 25m 12m S 5.8 0.2 0:22.03 httpd
22107 apache 15 0 412m 24m 11m S 5.8 0.2 0:14.28 httpd
22175 apache 15 0 415m 28m 14m S 5.8 0.2 0:14.48 httpd
22177 apache 15 0 415m 29m 15m S 5.8 0.2 0:14.81 httpd
22294 apache 15 0 414m 25m 12m S 5.8 0.2 0:13.70 httpd
22318 apache 15 0 412m 24m 11m S 5.8 0.2 0:14.16 httpd
23293 apache 15 0 414m 24m 11m S 5.8 0.2 0:06.70 httpd
23366 apache 15 0 415m 28m 14m S 5.8 0.2 0:06.78 httpd
24339 apache 15 0 411m 20m 8400 S 5.8 0.1 0:00.26 httpd
24342 apache 15 0 411m 20m 8220 S 5.8 0.1 0:00.19 httpd
21168 apache 15 0 415m 27m 13m S 3.9 0.2 0:21.94 httpd
21170 apache 15 0 415m 27m 13m S 3.9 0.2 0:21.98 httpd
21182 apache 15 0 415m 29m 15m S 3.9 0.2 0:22.26 httpd
22124 apache 15 0 414m 25m 12m S 3.9 0.2 0:14.94 httpd
22181 apache 15 0 414m 25m 12m S 3.9 0.2 0:14.44 httpd
22193 apache 15 0 415m 27m 13m S 3.9 0.2 0:14.14 httpd
Apache is currently using 6207 Megs of memory...
There are 245 Apache processes running at this time.
--------------------------------
So the load is high, but i have free RAM left and only running 245 Apache processes, out of a possible 600? I only show the first few lines of top ….
Or do I get this wrong, does each connection have an httpd process that is run, or are child/subsequent connections, not listed on under a ps ax??
I get the same results on the other web serves too...
I removed access logging, I disable access logging by commenting out the CustomLog directive in each virtualhost and then in httpd.com I set CustomLog value to /dev/null, this way I can keep error working too… is this ok? Here aer some of the httpd.con entries…
Keepalive is off
KeepAliveTimeout 3
MaxKeepAliveRequests 60
HostnameLookups Off
TraceEnable Off
UseCanonicalName Off
Here are loaded modules, I am not sure if I need them all, can I safely turn any off?
LoadModule actions_module modules/mod_actions.so
LoadModule alias_module modules/mod_alias.so
LoadModule asis_module modules/mod_asis.so
LoadModule auth_basic_module modules/mod_auth_basic.so
LoadModule auth_digest_module modules/mod_auth_digest.so
LoadModule authn_alias_module modules/mod_authn_alias.so
LoadModule authn_anon_module modules/mod_authn_anon.so
LoadModule authn_default_module modules/mod_authn_default.so
LoadModule authn_file_module modules/mod_authn_file.so
LoadModule authz_default_module modules/mod_authz_default.so
LoadModule authz_groupfile_module modules/mod_authz_groupfile.so
LoadModule authz_host_module modules/mod_authz_host.so
LoadModule authz_owner_module modules/mod_authz_owner.so
LoadModule authz_user_module modules/mod_authz_user.so
LoadModule autoindex_module modules/mod_autoindex.so
LoadModule cern_meta_module modules/mod_cern_meta.so
LoadModule cgi_module modules/mod_cgi.so
LoadModule deflate_module modules/mod_deflate.so
LoadModule dir_module modules/mod_dir.so
LoadModule env_module modules/mod_env.so
LoadModule expires_module modules/mod_expires.so
LoadModule ext_filter_module modules/mod_ext_filter.so
LoadModule geoip_module /usr/lib64/httpd/modules/mod_geoip.so
LoadModule headers_module modules/mod_headers.so
LoadModule include_module modules/mod_include.so
LoadModule info_module modules/mod_info.so
LoadModule log_config_module modules/mod_log_config.so
LoadModule logio_module modules/mod_logio.so
LoadModule mime_magic_module modules/mod_mime_magic.so
LoadModule mime_module modules/mod_mime.so
LoadModule negotiation_module modules/mod_negotiation.so
LoadModule proxy_module modules/mod_proxy.so
LoadModule rewrite_module modules/mod_rewrite.so
LoadModule setenvif_module modules/mod_setenvif.so
LoadModule status_module modules/mod_status.so
LoadModule userdir_module modules/mod_userdir.so
LoadModule usertrack_module modules/mod_usertrack.so
LoadModule vhost_alias_module modules/mod_vhost_alias.so
Thanks to all in advance.. and have a great day!
I am at the end of my rope.. :(
Thanks
Rob Morin
Systems Administrator
Infinity Labs Inc.
(514) 387-0638 Ext: 207
