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We have a WordPress site that keeps shutting down whenever we get around 100 users. WP super cache is already installed. Everytime the site goes down, we have to run service httpd restart.

Now, we're trying to figure out if there is anything in HTTPD.CONF can needs fine tuning (this is GoDaddy's default configuration for dedicated hosting, had to remove the comments since ServerFault limits the number of characters that be posted):

ServerTokens OS

ServerRoot "/etc/httpd"

PidFile run/httpd.pid

Timeout 120

KeepAlive On

MaxKeepAliveRequests 500

KeepAliveTimeout 5

<IfModule prefork.c>
 StartServers       1
 MinSpareServers    1
 MaxSpareServers    5
 ServerLimit        50
 MaxClients         50
 MaxRequestsPerChild  4000

<IfModule worker.c>
StartServers       1
MaxClients         50
MinSpareThreads    1
MaxSpareThreads    4
ThreadsPerChild    25
MaxRequestsPerChild  0

Listen 80

LoadModule auth_basic_module modules/mod_auth_basic.so
LoadModule auth_digest_module modules/mod_auth_digest.so
LoadModule authn_file_module modules/mod_authn_file.so
LoadModule authn_alias_module modules/mod_authn_alias.so
LoadModule authn_anon_module modules/mod_authn_anon.so
LoadModule authn_dbm_module modules/mod_authn_dbm.so
LoadModule authn_default_module modules/mod_authn_default.so
LoadModule authz_host_module modules/mod_authz_host.so
LoadModule authz_user_module modules/mod_authz_user.so
LoadModule authz_owner_module modules/mod_authz_owner.so
LoadModule authz_groupfile_module modules/mod_authz_groupfile.so
LoadModule authz_dbm_module modules/mod_authz_dbm.so
LoadModule authz_default_module modules/mod_authz_default.so
LoadModule ldap_module modules/mod_ldap.so
LoadModule authnz_ldap_module modules/mod_authnz_ldap.so
LoadModule include_module modules/mod_include.so
LoadModule log_config_module modules/mod_log_config.so
LoadModule logio_module modules/mod_logio.so
LoadModule env_module modules/mod_env.so
LoadModule ext_filter_module modules/mod_ext_filter.so
LoadModule mime_magic_module modules/mod_mime_magic.so
LoadModule expires_module modules/mod_expires.so
LoadModule deflate_module modules/mod_deflate.so
LoadModule headers_module modules/mod_headers.so
LoadModule usertrack_module modules/mod_usertrack.so
LoadModule setenvif_module modules/mod_setenvif.so
LoadModule mime_module modules/mod_mime.so
LoadModule dav_module modules/mod_dav.so
LoadModule status_module modules/mod_status.so
LoadModule autoindex_module modules/mod_autoindex.so
LoadModule info_module modules/mod_info.so
LoadModule dav_fs_module modules/mod_dav_fs.so
LoadModule vhost_alias_module modules/mod_vhost_alias.so
LoadModule negotiation_module modules/mod_negotiation.so
LoadModule dir_module modules/mod_dir.so
LoadModule actions_module modules/mod_actions.so
LoadModule speling_module modules/mod_speling.so
LoadModule userdir_module modules/mod_userdir.so
LoadModule alias_module modules/mod_alias.so
LoadModule rewrite_module modules/mod_rewrite.so
LoadModule proxy_module modules/mod_proxy.so
LoadModule proxy_balancer_module modules/mod_proxy_balancer.so
LoadModule proxy_ftp_module modules/mod_proxy_ftp.so
LoadModule proxy_http_module modules/mod_proxy_http.so
LoadModule proxy_connect_module modules/mod_proxy_connect.so
LoadModule cache_module modules/mod_cache.so
LoadModule suexec_module modules/mod_suexec.so
LoadModule disk_cache_module modules/mod_disk_cache.so
LoadModule file_cache_module modules/mod_file_cache.so
LoadModule mem_cache_module modules/mod_mem_cache.so
LoadModule cgi_module modules/mod_cgi.so
LoadModule version_module modules/mod_version.so

Include conf.d/*.conf

User apache
Group apache

ServerAdmin root@localhost

UseCanonicalName Off

DocumentRoot "/var/www/html"

<Directory />
    Options FollowSymLinks
    AllowOverride None

<Directory "/var/www/html">

    Options Indexes FollowSymLinks

    AllowOverride None

    Order allow,deny
    Allow from all


<IfModule mod_userdir.c>
    UserDir disable    

DirectoryIndex index.html index.html.var index.shtml index.cfm index.php index.htm

AccessFileName .htaccess

<Files ~ "^\.ht">
    Order allow,deny
    Deny from all

TypesConfig /etc/mime.types

DefaultType text/plain

<IfModule mod_mime_magic.c>
    MIMEMagicFile conf/magic

HostnameLookups Off

ErrorLog logs/error_log

LogLevel warn

LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\"" combined
LogFormat "%h %l %u %t \"%r\" %>s %b" common
LogFormat "%{Referer}i -> %U" referer
LogFormat "%{User-agent}i" agent

CustomLog logs/access_log combined

ServerSignature On

Alias /icons/ "/var/www/icons/"

<Directory "/var/www/icons">
    Options Indexes MultiViews
    AllowOverride None
    Order allow,deny
    Allow from all

<IfModule mod_dav_fs.c>
    DAVLockDB /var/lib/dav/lockdb

ScriptAlias /cgi-bin/ "/var/www/cgi-bin/"

<Directory "/var/www/cgi-bin">
    AllowOverride None
    Options None
    Order allow,deny
    Allow from all

IndexOptions FancyIndexing VersionSort NameWidth=* HTMLTable

AddIconByEncoding (CMP,/icons/compressed.gif) x-compress x-gzip

AddIconByType (TXT,/icons/text.gif) text/*
AddIconByType (IMG,/icons/image2.gif) image/*
AddIconByType (SND,/icons/sound2.gif) audio/*
AddIconByType (VID,/icons/movie.gif) video/*

AddIcon /icons/binary.gif .bin .exe
AddIcon /icons/binhex.gif .hqx
AddIcon /icons/tar.gif .tar
AddIcon /icons/world2.gif .wrl .wrl.gz .vrml .vrm .iv
AddIcon /icons/compressed.gif .Z .z .tgz .gz .zip
AddIcon /icons/a.gif .ps .ai .eps
AddIcon /icons/layout.gif .html .shtml .htm .pdf
AddIcon /icons/text.gif .txt
AddIcon /icons/c.gif .c
AddIcon /icons/p.gif .pl .py
AddIcon /icons/f.gif .for
AddIcon /icons/dvi.gif .dvi
AddIcon /icons/uuencoded.gif .uu
AddIcon /icons/script.gif .conf .sh .shar .csh .ksh .tcl
AddIcon /icons/tex.gif .tex
AddIcon /icons/bomb.gif core

AddIcon /icons/back.gif ..
AddIcon /icons/hand.right.gif README
AddIcon /icons/folder.gif ^^DIRECTORY^^
AddIcon /icons/blank.gif ^^BLANKICON^^

DefaultIcon /icons/unknown.gif
ReadmeName README.html
HeaderName HEADER.html

IndexIgnore .??* *~ *# HEADER* README* RCS CVS *,v *,t

AddLanguage ca .ca
AddLanguage cs .cz .cs
AddLanguage da .dk
AddLanguage de .de
AddLanguage el .el
AddLanguage en .en
AddLanguage eo .eo
AddLanguage es .es
AddLanguage et .et
AddLanguage fr .fr
AddLanguage he .he
AddLanguage hr .hr
AddLanguage it .it
AddLanguage ja .ja
AddLanguage ko .ko
AddLanguage ltz .ltz
AddLanguage nl .nl
AddLanguage nn .nn
AddLanguage no .no
AddLanguage pl .po
AddLanguage pt .pt
AddLanguage pt-BR .pt-br
AddLanguage ru .ru
AddLanguage sv .sv
AddLanguage zh-CN .zh-cn
AddLanguage zh-TW .zh-tw

LanguagePriority en ca cs da de el eo es et fr he hr it ja ko ltz nl nn no pl pt pt-BR ru sv zh-CN zh-TW

ForceLanguagePriority Prefer Fallback
AddType application/x-compress .Z
AddType application/x-gzip .gz .tgz
AddHandler type-map var

AddType text/html .shtml
AddOutputFilter INCLUDES .shtml

Alias /error/ "/var/www/error/"

<IfModule mod_negotiation.c>
<IfModule mod_include.c>
    <Directory "/var/www/error">
        AllowOverride None
        Options IncludesNoExec
        AddOutputFilter Includes html
        AddHandler type-map var
        Order allow,deny
        Allow from all
        LanguagePriority en es de fr
        ForceLanguagePriority Prefer Fallback


BrowserMatch "Mozilla/2" nokeepalive
BrowserMatch "MSIE 4\.0b2;" nokeepalive downgrade-1.0 force-response-1.0
BrowserMatch "RealPlayer 4\.0" force-response-1.0
BrowserMatch "Java/1\.0" force-response-1.0
BrowserMatch "JDK/1\.0" force-response-1.0

BrowserMatch "Microsoft Data Access Internet Publishing Provider" redirect-carefully
BrowserMatch "MS FrontPage" redirect-carefully
BrowserMatch "^WebDrive" redirect-carefully
BrowserMatch "^WebDAVFS/1.[0123]" redirect-carefully
BrowserMatch "^gnome-vfs/1.0" redirect-carefully
BrowserMatch "^XML Spy" redirect-carefully
BrowserMatch "^Dreamweaver-WebDAV-SCM1" redirect-carefully

AddType application/x-httpd-php .php
AddType application/x-httpd-php-source .phps

Loaded modules are:

core prefork http_core mod_so mod_auth_basic mod_auth_digest mod_authn_file mod_authn_alias mod_authn_anon mod_authn_dbm mod_authn_default mod_authz_host mod_authz_user mod_authz_owner mod_authz_groupfile mod_authz_dbm mod_authz_default util_ldap mod_authnz_ldap mod_include mod_log_config mod_logio mod_env mod_ext_filter mod_mime_magic mod_expires mod_deflate mod_headers mod_usertrack mod_setenvif mod_mime mod_dav mod_status mod_autoindex mod_info mod_dav_fs mod_vhost_alias mod_negotiation mod_dir mod_actions mod_speling mod_userdir mod_alias mod_rewrite mod_proxy mod_proxy_balancer mod_proxy_ftp mod_proxy_http mod_proxy_connect mod_cache mod_suexec mod_disk_cache mod_file_cache mod_mem_cache mod_cgi mod_version mod_fcgid mod_perl mod_php5 mod_proxy_ajp mod_python mod_ssl

Is there anything obviously wrong with this configuration? What do we need to do to optimize this?

share|improve this question
Which Apache MPM are you using? –  EEAA Aug 9 '11 at 4:42
Define "shutting down" - does the service actually shut down, or are your users seeing a 503 error (due to your low MaxClients setting, which is the direction that @ErikA is going in)? –  Shane Madden Aug 9 '11 at 4:55
@Shane - httpd service turns off and we need to restart it. Not sure if it's a 503 or 404 or something else that we are getting. I'll try to figure that out next time it shuts down. Right now, we have someone in front of an SSH terminal at all times ready to hit enter on service httpd restart. –  StackOverflowNewbie Aug 9 '11 at 5:10
Just happened again. Not getting any HTTP errors. Instead, I just got an "Aborted" message (saw think in Firebug). –  StackOverflowNewbie Aug 9 '11 at 5:15
@stackoverflownewbie, Try to increase this value and see if it helps. –  HUB Aug 9 '11 at 8:49

3 Answers 3

up vote 1 down vote accepted

Try bumping up these values:

ServerLimit        50
MaxClients         50

Doing this has the potential to double the amount of memory that Apache is consuming, though, so make sure that you have enough RAM to support this.

share|improve this answer

A few weeks ago I needed to tune an apache web server for a client, and although the process is straight-forward (see memory used by processes, server memory available, etc.), it's also a bit tedious. I expected to find a ready made application / script to do the number crunching, but my search didn't turn up anything, so I rolled my own. ;-) I figured you might find it useful too. You can find the weblog entry here https://surniaulula.com/2012/11/09/check-apache-httpd-mpm-config-limits/ and the script on Google Code as well.



share|improve this answer

There's a LOT obviously wrong with this configuration - but changing it isn't really going to help: tuning improves performance it does not eliminate crashes.

this is GoDaddy's default configuration

erm, perhaps not my first choice for a hosting service.

It does rather beg the question of what scope you have for resolving the problem assuming you can isolate it.

Since you are running prefork, it seems very odd that something is causing the root instance of the httpd to crash under load. It's much more likely to do with the software/hardware your running it on than the number/type of requests.

The only proactical solution (other than ensuring that you've got all the vendor patches installed, and run extensive hardware diagnostics) is to enable core dumops and start debugging.

share|improve this answer

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