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<Directory /var/www/vhosts/rmohan.com/httpdocs> RewriteEngine on rewriterule ^(.+).htm$ /$1.php [r=301,nc] RewriteRule ^community community.php [nc] ErrorDocument 404 /index.php </Directory> RewriteCondthat checks if the requested file exists:
Great, but that’s not what I was looking for. Instead I needed to Rewrite only if a specific folder existed. The solution turns out to be this:
You need DOCUMENT_ROOT as the RewriteCond -d checks for the full path
One of the advantages of maintaing a popular project like XAMPP is the immense amount of community feedback you get. In other words: your inbox is a daily challenge. PHP 5.3 incompatibilities are hot topics these days. Here’s an Apache related one which hits my inbox on a very regular basis. Variant 1Apache complains about:
The “Unable to open logs” in this error message is very confusing and often points people in the wrong direction. There is nothing wrong with directory or file permissions, in this case there is simply another process already occupying port 80 and that prevents Apache from binding to this port. Find out which process is using this port and stop it. Alternatively let Apache use another port. Variant 2Actually if it’s a permission issue you will see:
Here Apache tried to bind port 80, but got rejected by the system because the Apache wasn’t started as root. On Unix systems only processes by the user root are allowed to bind ports below 1024. To fix this: Let Apache bind to a port above 1024 or start Apache as root. Variant 3If you just get this error, without “no listening sockets available…”:
Looks very similar to the first variant, but in this case you probably just have multiple “Listen 80” directives in you Apache’s configuration. Become aware of all Include directives in your httpd.conf and remove all Listen duplicates. The Apache HTTP Server has been the most popular web server on the Internet since April 1996 and is one of the most widely used open source software packages. In fact, the latest Netcraft Web Server Survey reports that more than half of all active web sites use Apache, making it more widely used than all other Web servers combined. So it’s no surprise that we get lots of questions about Apache HTTP Server installation procedures. Fortunately, we have tons of experience with Apache installations, and we’ve distilled our years of experience into this handy tutorial. Before You StartThis article assumes that you have Red Hat/CentOS Linux with a proper build environment setup. If you do not have GCC installed you can get this with all the required packages like this: yum groupinstall "Development Libraries" You should now be ready to install Apache! Meat & PotatoesWhen we install Apache HTTP Server either for ourselves a client — small or large — we follow a “standard” configuration setup that’s very easy to build on later. For the most part we use CentOS or Red Hat Enterprise edition servers, but these steps should work on any Unix system. This might not be true for AIX, which requires a little more hand-holding to make sure the compiler is installed correctly. The steps we’ll cover in this article are:
Download ApacheThe first step is to download the Apache source code, not binaries or RPMs. We believe that using the source code gives the best performing, most flexible installation of Apache. If you follow a few simple steps the actual “installation” procedure is not difficult, and you’ll have a good foundation to add or remove features later. To download the source source code, go to OpenLogic Exchange (OLEX) or the Apache downloads site and look for the latest ZIP, TGZ, or BZ2 file (currently version 2.2.11). Compiling/Installing the Source for ApacheWe like to keep our source downloads in ~/Software/ so it’s easy go back and re-compile and re-install the binaries if we need to add a module or two. With the source saved under ~/Software/httpd-2.2.11, compile Apache HTTP Server with the following configure string: [root@coco ~]# cd ~/Software/httpd-2.2.11 [root@coco httpd-2.2.11]# "./configure" "--enable-ssl" "--enable-proxy" "--enable-proxy-balancer" "--enable-rewrite" "--enable-headers" "--enable-deflate" "--enable-cache" "--enable-expires" "--enable-mem-cache" "--enable-disk-cache" "--enable-file-cache" "--with-mpm=worker" "--disable-cgi --disable-asis" "--disable-autoindex" "--disable-userdir" Here’s a brief explanation of the configuration options shown above:
Next, run the following to install Apache HTTP Server: [root@coco httpd-2.2.11]# make && make install The Apache server should now be installed in /usr/local/apache2, which is the default installation directory. To change the Apache installation directory you’ll need to add the –prefix=/my/directory/apache2 switch to the configure string, and then run the make && make install command as shown above. Apache Startup ScriptThe easiest and fastest way to start Apache is to copy /usr/local/apache2/bin/apachectl to /etc/init.d/apache. This will allow you to do /etc/init.d/apache start|stop|restart. If you want a script that has more feedback you can use the following: #!/bin/bash
# httpd Startup script for the Apache HTTP Server
# chkconfig: 2345 85 15
# description: Apache is a World Wide Web server. It is used to serve
# HTML files and CGI.
# processname: httpd
# config: /usr/local/apache2/conf/httpd.conf
# pidfile: /var/run/apache2.pid
# Source function library.
. /etc/rc.d/init.d/functions
# Start httpd in the C locale by default.
HTTPD_LANG=${HTTPD_LANG-"C"}
# This will prevent initlog from swallowing up a pass-phrase prompt if
# mod_ssl needs a pass-phrase from the user.
INITLOG_ARGS=""
# Path to the apachectl script, server binary, and short-form for messages.
apachectl=/usr/local/apache2/bin/apachectl
httpd=${HTTPD-/usr/local/apache2/bin/httpd}
prog=httpd
pidfile=${PIDFILE-/var/run/apache2.pid}
lockfile=${LOCKFILE-/var/lock/subsys/apache2}
RETVAL=0
start() {
echo -n $"Starting $prog: "
LANG=$HTTPD_LANG daemon $httpd $OPTIONS
RETVAL=$?
echo
[ $RETVAL = 0 ] && touch ${lockfile}
return $RETVAL
}
stop() {
echo -n $"Stopping $prog: "
killproc $httpd
RETVAL=$?
echo
[ $RETVAL = 0 ] && rm -f ${lockfile} ${pidfile}
}
reload() {
echo -n $"Reloading $prog: "
if ! LANG=$HTTPD_LANG $httpd $OPTIONS -t >&/dev/null; then
RETVAL=$?
echo $"not reloading due to configuration syntax error"
failure $"not reloading $httpd due to configuration syntax error"
else
killproc $httpd -HUP
RETVAL=$?
fi
echo
}
# See how we were called.
case "$1" in
start)
start
;;
stop)
stop
;;
status)
status $httpd
RETVAL=$?
;;
restart)
stop
start
;;
condrestart)
if [ -f ${pidfile} ] ; then
stop
start
fi
;;
reload)
reload
;;
graceful|help|configtest|fullstatus)
$apachectl $@
RETVAL=$?
;;
*)
echo $"Usage: $prog {start|stop|restart|condrestart|reload|status|fullstatus|graceful|help|configtest}"
exit 1
esac
exit $RETVAL
Apache Configuration FileThe main configuration file we use as a template for Apache servers has a few different sections that are important to understand. # =================================================
# Basic Settings
# =================================================
ServerName %{SERVER_NAME}
ServerRoot "/usr/local/apache2"
PidFile "/var/run/apache2.pid"
# =================================================
# Performance Settings
# =================================================
Timeout 30
KeepAlive On
MaxKeepAliveRequests 500
KeepAliveTimeout 2
<IfModule mpm_prefork_module>
StartServers 1
MinSpareServers 1
MaxSpareServers 10
MaxClients 25
MaxRequestsPerChild 1000
</IfModule>
<IfModule mpm_worker_module>
ServerLimit 16
StartServers 2
MaxClients 40
MinSpareThreads 5
MaxSpareThreads 20
ThreadsPerChild 20
MaxRequestsPerChild 5000
</IfModule>
The Basic Settings section just defines the root directory of Apache, but the Performance Settings section has a few noteworthy options. We have a Timeout of 30 seconds, which is enough for most setups (the default of 300 is way too long). We enable KeepAlive, but the KeepAlive timeout is only 2 seconds. This allows each user to get their own connection, but the connection will close as soon as they download the page they requested (you can play with this timeout, but you’ll most likely want to have it set somewhere in the 1-5 sec range). Next, we setup prefork and worker based on the number of CPUs that are installed on the Apache server. # ================================================= # General Settings # ================================================= Listen 80 # Listen 443 User www Group www ServerAdmin webmaster@openlogic.com UseCanonicalName Off ServerTokens Prod ServerSignature Off HostnameLookups Off ExtendedStatus On # ================================================= # Modules # ================================================= #LoadModule dummy_module /usr/lib/apache2/modules/mod_dummy.so In the General Settings section we set Listen to port 80, but we also have port 443 as an option to choose from (we’ll show you how to setup a https/SSL/secure virtual host later). User and Group are set to the www user, which is a system user (note that on Red Hat you create a system user with the -r switch adduser -r www). We don’t want the server to look up hostname or show a signature to our users, so those options are disabled. The ExtendedStatus option is enabled for monitoring reasons. And in the Modules section, the dummy module is there in case we want to install PHP later on. # ================================================= # Access Control # ================================================= <Directory /> Options FollowSymLinks AllowOverride None Order deny,allow Deny from all </Directory> <DirectoryMatch "^/.*/.svn/"> ErrorDocument 403 /404.html Order allow,deny Deny from all Satisfy All </DirectoryMatch> <FilesMatch "^.ht"> Order allow,deny Deny from all Satisfy All </FilesMatch> # ================================================= # MIME Encoding # ================================================= DefaultType text/plain TypesConfig conf/mime.types AddType application/x-compress .Z AddType application/x-gzip .gz .tgz AddType application/x-x509-ca-cert .crt AddType application/x-pkcs7-crl .crl Needless to say, the Access Control section contains some important options. Deny from all makes sure we have to allow access to any directory that’s used in the Apache configuration. Then, we make sure that users don’t have access to .svn directories or .ht files. In the MIME Encoding section we have a minimal mime.type setup for the deflate and SSL modules. # =================================================
# Logs
# =================================================
LogLevel warn
LogFormat "%h %l %u %t "%r" %>s %b "%{Referer}i" "%{User-Agent}i"" combined
ErrorLog /usr/local/apache2/logs/error_log
# Mark requests for the robots.txt file
SetEnvIf Request_URI "^/robots.txt$" dontlog
SetEnvIf Request_URI "^/monit/token$" dontlog
# =================================================
# SSL Configuration
# =================================================
SSLPassPhraseDialog builtin
SSLSessionCache shmcb:/usr/local/apache2/logs/ssl_scache(512000)
SSLSessionCacheTimeout 300
SSLMutex file:/usr/local/apache2/logs/ssl_mutex
SSLRandomSeed startup builtin
SSLRandomSeed connect builtin
Next, we setup the LogFormat for use in our virtual hosts and the server error log file. We also have two dontlog Env settings to remove the robot.txt and monit/token hits from the log. (We’ll show how this is used when we create the virtual host.) We also setup a default SSL configuration for the server. # ================================================= # Mod Status for Monitoring # ================================================= <VirtualHost 127.0.0.1:80> <Location /server-status> SetHandler server-status Order Deny,Allow Deny from all Allow from localhost Allow from 127.0.0.1 </Location> </VirtualHost> # ================================================= # Include Extra Configs # ================================================= Include conf/extra/httpd-myblog.com.conf In the Mod Status for Monitoring section we get to the server monitoring setup. We start by allowing only access from localhost, and we specify that it will only listen to the 127.0.0.1 IP. This is a good setup for tools like GroundWork and Hyperic. The last line includes a virtual host configuration file. Now let’s have a look at the virtual host. Virtual Hosts Using a Name-Based SetupWe like to configure our httpd.conf with server-wide settings while keeping it free of actual content hosting elements or mod_proxy/mod_jk configurations. In this example we have a blog that’s running on a Ruby on Rails back-end with three Thin servers listening to ports 8000-8002 (Thin an application server that can be used for RoR as an alternative to Tomcat or Mongrel). # -------------------------------------------------------- # Always Keep the Host Header # -------------------------------------------------------- ProxyPreserveHost On # -------------------------------------------------------- # Rails Cluster # -------------------------------------------------------- <Proxy balancer://rails-cluster> BalancerMember http://127.0.0.1:8000 BalancerMember http://127.0.0.1:8001 BalancerMember http://127.0.0.1:8002 </Proxy> This setup has three servers in a proxy_balancer cluster that you can access using balancer://rails-cluster/ just as though it was one server. # --------------------------------------------------------
# Name-Based Virtual Hosting
# --------------------------------------------------------
NameVirtualHost *:80
<VirtualHost *:80>
DocumentRoot "/var/www/myblog.com/current/public"
ServerName www.myblog.com
ServerAlias myblog.com
# -------------------------------------------------
# Rewrite Rules
# -------------------------------------------------
RewriteEngine on
# Force www.myblog.com and make sure we use a 301 HTTP code for the
# redirect. This is a SEO must.
RewriteCond %{HTTP_HOST} !^www.myblog.com [NC]
RewriteCond %{HTTP_HOST} !^$
RewriteRule ^/(.*) http://www.myblog.com/$1 [L,R=301]
# --------------------------------------------------------
# List of URLs Not to Proxy
# --------------------------------------------------------
ProxyPass /system !
ProxyPass /images !
ProxyPass /stylesheets !
ProxyPass /javascripts !
ProxyPass /monit/token !
# Send everything else to the proxy_balancer cluster of rails servers
ProxyPass / balancer://rails-cluster/
ProxyPassReverse / balancer://rails-cluster/
<Directory "/var/www/myblog.com/current/public">
Options FollowSymLinks
AllowOverride None
Order allow,deny
Allow from all
</Directory>
# Before you restart the server you need to create the logs/myblog.com
# directory.
# We are also adding the dontlog environment variable here to stop
# logging the set entries. (This is configured in your httpd.conf)
ErrorLog "logs/myblog.com/error_log"
CustomLog "logs/myblog.com/access_log" combined env=!dontlog
# --------------------------------------------------------
# Deflate Module Configuration
# --------------------------------------------------------
<IfModule deflate_module>
AddOutputFilterByType DEFLATE text/plain
AddOutputFilterByType DEFLATE text/xml
AddOutputFilterByType DEFLATE application/xhtml+xml
AddOutputFilterByType DEFLATE text/css
AddOutputFilterByType DEFLATE application/xml
AddOutputFilterByType DEFLATE image/svg+xml
AddOutputFilterByType DEFLATE application/rss+xml
AddOutputFilterByType DEFLATE application/atom_xml
AddOutputFilterByType DEFLATE application/javascript
AddOutputFilterByType DEFLATE application/x-javascript
AddOutputFilterByType DEFLATE application/x-httpd-php
AddOutputFilterByType DEFLATE application/x-httpd-fastphp
AddOutputFilterByType DEFLATE application/x-httpd-eruby
AddOutputFilterByType DEFLATE text/html
BrowserMatch ^Mozilla/4 gzip-only-text/html
BrowserMatch ^Mozilla/4.0[678] no-gzip
</IfModule>
# =============================================
# Configure Expires Module
# =============================================
<IfModule mod_expires.c>
ExpiresActive On
ExpiresDefault "access plus 1 seconds"
ExpiresByType text/html "access plus 1 seconds"
ExpiresByType image/gif "access plus 1 week"
ExpiresByType image/jpeg "access plus 1 week"
ExpiresByType image/png "access plus 1 week"
ExpiresByType text/css "access plus 1 week"
ExpiresByType text/javascript "access plus 1 week"
ExpiresByType application/x-javascript "access plus 1 week"
ExpiresByType text/xml "access plus 1 seconds"
</IfModule>
</VirtualHost>
There’s a lot of information here, so lets take it step by step. First, we setup a server with the name www.myblog.com that also listens to myblog.com, but by using mod_rewrite we force everyone to www.myblog.com with a 301 redirect. Next, we setup all of the static content that we want Apache to serve from the local file system using ProxyPass with a ! to say “do not proxypass” these directories, and then we send everything else to the balancer cluster. We setup the access rights to the static directory where our content (like images, JavaScript, uploaded files, and CSS) is stored. Then, we setup the virtualhosts log file in its own directory inside the logs directory. The mod_deflate and mod_expires configurations work for most setups, but this piece needs to be monitored and tuned to your setup. We’ve seen the mod_expires setup cause problems using Rails and authentication. Now, off to a secure.myblog.com virtual host: <VirtualHost _default_:443>
DocumentRoot "/var/www/myblog.com/current/public"
ServerName secure.myblog.com
ServerAlias www.myblog.com myblog.com
RewriteCond %{HTTP_HOST} !^secure.myblog.com [NC]
RewriteCond %{HTTP_HOST} !^$
RewriteRule ^/(.*) https://secure.myblog.com/$1 [L,R=301]
# --------------------------------------------------------
# List of URLs Not to Proxy
# --------------------------------------------------------
ProxyPass /system !
ProxyPass /images !
ProxyPass /stylesheets !
ProxyPass /javascripts !
ProxyPass / balancer://rails-cluster/
ProxyPassReverse / balancer://rails-cluster/
ErrorLog "logs/myblog.com/error_log"
CustomLog "logs/myblog.com/access_log" combined env=!donlog
# --------------------------------------------------------
# SSL Certificates
# --------------------------------------------------------
SSLEngine on
SSLCertificateFile /usr/local/apache2/ssl/secure.myblog.com.crt
SSLCertificateKeyFile /usr/local/apache2/ssl/secure.myblog.com.key
# --------------------------------------------------------
# Deflate Module Configuration
# --------------------------------------------------------
<IfModule deflate_module>
AddOutputFilterByType DEFLATE text/plain
AddOutputFilterByType DEFLATE text/xml
AddOutputFilterByType DEFLATE application/xhtml+xml
AddOutputFilterByType DEFLATE text/css
AddOutputFilterByType DEFLATE application/xml
AddOutputFilterByType DEFLATE image/svg+xml
AddOutputFilterByType DEFLATE application/rss+xml
AddOutputFilterByType DEFLATE application/atom_xml
AddOutputFilterByType DEFLATE application/javascript
AddOutputFilterByType DEFLATE application/x-javascript
AddOutputFilterByType DEFLATE application/x-httpd-php
AddOutputFilterByType DEFLATE application/x-httpd-fastphp
AddOutputFilterByType DEFLATE application/x-httpd-eruby
AddOutputFilterByType DEFLATE text/html
BrowserMatch ^Mozilla/4 gzip-only-text/html
BrowserMatch ^Mozilla/4.0[678] no-gzip
</IfModule>
# =============================================
# Configure Expires Module
# =============================================
<IfModule mod_expires.c>
ExpiresActive On
ExpiresDefault "access plus 1 seconds"
ExpiresByType text/html "access plus 1 seconds"
ExpiresByType image/gif "access plus 1 week"
ExpiresByType image/jpeg "access plus 1 week"
ExpiresByType image/png "access plus 1 week"
ExpiresByType text/css "access plus 1 week"
ExpiresByType text/javascript "access plus 1 week"
ExpiresByType application/x-javascript "access plus 1 week"
ExpiresByType text/xml "access plus 1 seconds"
</IfModule>
# --------------------------------------------------------
# Document Root /
# --------------------------------------------------------
<Directory "/var/www/myblog.com/current/public">
Options FollowSymLinks
AllowOverride None
Order allow,deny
Allow from all
</Directory>
# -------------------------------------------------
# Fixing Yet Another IE 6 Bug
# -------------------------------------------------
BrowserMatch ".*MSIE.*" nokeepalive ssl-unclean-shutdown downgrade-1.0 force-response-1.0
# -------------------------------------------------
# Add this to the request header so that
# Rails puts the correct redirect in place
# -------------------------------------------------
RequestHeader set X_FORWARDED_PROTO 'https'
</VirtualHost>
This is very similar to the port 80 virtual host of the same name. The biggest difference is with the SSL certificates and the bottom SSL/https settings to fix issues with Mongrel/Rails and IE6. You can’t configure mod_expires and mod_deflate in the main configuration file and have the virtual host inheret the configuration, so the best solution to be dry is to put these settings in their own mod_deflate.conf and mod_expires.conf and then include the named configuration files in each virtualhosts configuration file like so: Include conf/mod_deflate.conf Include conf/mod_expires.conf Finishing UpApache with mod_proxy rocks. After working through the above steps we have an Apache installation that is ready to be expanded to a high performance web server or proxy server, or both. We like to start with this setup and then build from here. If you need to get more concurrent clients and throughput on your Apache server, take a look at your available memory and CPU cycles and consider doing something like this: <IfModule mpm_worker_module> ThreadLimit 100 StartServers 5 MaxClients 1000 MinSpareThreads 100 MaxSpareThreads 1000 ThreadsPerChild 100 MaxRequestsPerChild 0 </IfModule> This is a high threads and low processes setup, and to get the number of processes that Apache will use simply divide MaxClients by ThreadPerChild. So, this gives us 10 processes each with a maximum of 100 threads, with a maximum of 1000 clients total. Depending on the server and type of content that you are serving you can load test and increase these settings if you need more than 1000 concurrent users. We’re very big fans of mod_proxy, and we use mod_proxy_ajp in place of mod_jk every chance we get. We also talk a lot of customers into using mod_proxy over mod_jk if they’re using Apache 2.2.x. Using this setup to include the virtual hosts that the server runs, it’s easy to add and remove new websites. It also provides a good overview of what’s running on the server. Sometimes you need to truncate/empty a file to zero byte length. For example, you have a big file that contains various logs and the size is too big to open it easily. Of course, you can remove this file and touch it again. But this way you will have to play with permissions and file ownership. There is a simple command that will truncate the file to zero length without affecting any permissions. # > filename If the file already exists, it will be truncated to zero bytes, else this command will create an empty file. This is great for truncating big log files, eg. Apache error logs. > filename eg > nohup.out I have installed apache 2.2 on RHEL 5.7. It is working over ssl connection. I want to use rotatelog feature provided by apache. ErrorLog “|/apps/apache/bin/rotatelogs /mnt/nfs4/logs/apache/error_log.%Y-%m-%d 10M” <IfModule logio_module> CustomLog “|/apps/apache/bin/rotatelogs /mnt/nfs4/logs/apache/access_log.%Y-%m-%d 50K” combine ErrorLog “/mnt/nfs4/logs/apache/error_log” ErrorLog “|/usr/local/apache2.22/bin/rotatelogs /usr/local/apache2.22/logs/error_log.%Y-%m-%d 10M” CustomLog “|/usr/local/apache2.22/bin/rotatelogs /usr/local/apache2.22/logs/access_log.%Y-%m-%d 50M” common SSLLOGS ErrorLog “|/usr/local/apache2.22/bin/rotatelogs /usr/local/apache2.22/logs/ssl_error_log.%Y-%m-%d 100M” CustomLog “| /usr/local/apache2.22/bin/rotatelogs /usr/local/apache2.22/logs/ssl_request_log.%Y-%m-%d 100M” \
1) Install Cronolog. You can download it here: The installation is pretty straightforward with the standard commands Linux# ./configure 2) Add these lines to your httpd.conf file (and don$B!G(Bt forget to comment out ErrorLog $B!H(B|/usr/local/sbin/cronolog -l /var/log/httpd/Ryans-error_log CustomLog $B!H(B|/usr/local/sbin/cronolog -l /var/log/httpd/Ryans-access_log 3) Restart your httpd server. Linux# /etc/init.d/httpd restart almost exclusively use cronolog over logrotate. Logrotate comes with Debian, One of of the reasons why I use cronolog is that all the configuration e.g. in a lighttpd config file, you could put : accesslog.filename = “|/usr/bin/cronolog –symlink=”/var/log/webs/access.log And all get a a new log file every week without any other configuration. Or accesslog.filename = “|/usr/bin/cronolog –symlink=”/var/log/webs/access.log is would work: ErrorLog “|/usr/bin/cronolog /path/to/logs/%Y-%m-%d/error.log”
How do I rotate log files under Linux operating system?
ou need use tool called logrotate, which is designed to ease administration of systems that generate large numbers of log files. It allows automatic rotation, compression, removal, and mailing of log files. Each log file may be handled daily, weekly, monthly, or when it grows too large. With this tool you keep logs longer with less disk space. Default configuration fileThe default configuration file is /etc/logrotate.conf: /var/log/httpd/*.log {
weekly
rotate 52
compress
missingok
notifempty
sharedscripts
postrotate
/bin/kill -HUP `cat /var/run/httpd.pid 2>/dev/null` 2> /dev/null || true endscript
}
Where,
grep -v ‘^#’ /etc/httpd/conf/httpd.conf | grep -v ‘^$’ Redirect to the file grep -v ‘^#’ /etc/httpd/conf/httpd.conf | grep -v ‘^$’ > test
Modular structure of apache is one of the reason for its global dominance among webservers.We have the flexibility to adding or droping modules.Before we deal with apache prefork MPM we need to have a basic idea about apache Multi Processing Modules,Multi processing Modules (MPM) are the multiple request (hundreds to kilos) handling ‘department’ of apache.We can compare MPM as ‘valve’ of apache , it accept requests, spawn the child processes according to the inflow of requests and assign the child process for the incoming connections. Since prefork have a one process per thread structure it can provide isolation among different connections. So we can say that it is more secure at the cost of more RAM and CPU power. Worker MPM needs less RAM and CPU power but does not provide same level of request-to-request isolation as a process-based MPM does.Now let us look in to the prefork MPM tuning which is more common MPM than worker. Prefork Directives Example for prefork directives StartServers 8 StartServers : Number of apache child processes generated during the apache startup. MinSpareServers: Spare servers are child processes in idle(not handling any requests). If the total idle processes are less than MaxSpareServers: If the total idle child processes is more than this directive , then parent pocess will kill additional idle processes. MaxClients: This is the most important MPM directive for tuning apache performance.Parent process will dynamically spawn new child processes as the incoming request raises. MaxClients is the maximum child processes created for handling requests or in other words it is the max simultaneous requests apache can handle. This value should be optimal. If it is too low apache can only handle few requests and excess requests will be queued and it may get timed out.If it is too high server will begin to swap and it seriously affects entire server performance. MaxRequestsPerChild: After handling this much requests child process will die .MaxRequestsPerChild is the requests that a child process will handle in its life time.If it is too low in a busy server, apache will utilize a good CPU power for killing and spawning new child processes which may cause more CPU burden. But at the same time it is always good to recycle it in a timely manner, otherwise it may cause common issues like memory leak , process bloat etc. How to set MaxClients. Before choosing a value we need to analyze the server , i.e check the RAM size and applications running other than apache like mysql , java applications etc. Then roughly calculate the memory dedicated for those applications . For example ,we might have defined innodb buffer spool size for mysql and java heap size for java applications . Substract that much memory from total RAM size. Suppose you have 2 GB RAM and 500 MB allocated for mysql(it depends on your DB size) and 250 for java and reserved some memory for system applications ,in this setup we can reserve memory up to 1 GB for apache . On next step we need to calculate avereage process memory usage for apache. For calculating it , during the peak traffic time run the following command ps aux| awk ‘/apach[e]/{total+=$6}END{print total}’ this calculates total physical memory used by all apache process , to calculate average memory usage ,devide above value with total apache processes . MaxClients <= 1G/35 M = 30. We can reduce avg memory usage by removing unwanted apache modules and using php cache like PHP op-code cache/accelerator .If serever have good traffic, then fix the MaxRequestsPerChild deirective some higher values like 2000. Thoroughly observe server for some days after tuning , some time you need to tweak it 2 – 3 times for getting the best result. Good Luck! IPMP, or IP Multipathing, is used to provide redundant network connections for your Solaris servers. When IPMP was first release it used a probe based method for failure detection. This required an IP address to be placed on all NIC’s in the IPMP group, even if the NIC was just being used a test interface. Also, the probe based methodology for failure detection would send pings out every 2 seconds and would wait for 5 failures before failing over the IP addresses to another NIC in the IPMP group. This means that a network connection would be down for 10 seconds
before the failover occurred. Starting with Solaris 9 link-based IPMP was released. This uses the interfaces link state to determine the status of the network connection for failover/failback purposes. With link-based IPMP the failover will occur instantly when a link goes down. Since the failover is instantaneous and no extra IP addresses are required to build test interfaces, link-based IPMP is the preferred way to build redundant network interfaces on Solaris. IPMP requires that each NIC has a unique MAC address. Before configuring IPMP verify that the local-mac-address? Setting on the system PROM is set to true. # eeprom local-mac-address? If it’s not set to true then run the following command to change the setting and then reboot the system # eeprom local-mac-address?=true Link based IPMP can be configured as active/active or active/passive. Examples of both are provided below. Active/Passive: If your server is only using 1 IP address you will have to configure your IPMP as Active/ Passive. Here is a sample configuration. krishbe$ /etc/hostname.e1000g0 krishbe$/etc/hostname.e1000g1 The standby keyword is used on the passive interfaces. No hostname or IP address should be assigned to this NIC.This configuration will result in the following after a system reboot. krishbe$ ifconfig -a An attempt to assign an IP address to a standby interface will cause that IP to be configured on another NIC in the IPMP group. Notice in the following example an attempt to assign an IP address to e1000g1 will result in a new logical interface being configured on e1000g0. As long as the link status of one NIC in the IPMP group is good, then the standby interface will not allow any IP addresses to be configured on it. krishbe$ ifconfig e1000g1 addif 192.168.3.33 up In an active/passive configuration you can setup as many virtual IP address on the active NIC as you want. However, if multiple IP addresses are to be used then it would probably make sense to use an active/active configuration for load balancing purposes. Active/Active: If your server uses multiple IP address on the same network you can spread your network load across all NIC’s in your IPMP group. The following example shows 2 IP address on 2 NIC’s. krishbe$ cat /etc/e1000g0 krishbe$ cat /etc/e1000g1 This configuration will result in the following after a system reboot. krishbe$ ifconfig -a To test failover, you can do the hard way of pulling the cables or use if_mpadm command as follows: To failover: LAB: krishbe$ cat /etc/hostname.bge0 krishbe$ cat /etc/hostname.nxge0 krishbe$ ifconfig -a krishbe$ if_mpadm -d bge0 krishbe$ ifconfig -a krishbe$ if_mpadm -r bge0 krishbe$ ifconfig -a |
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