XCache is awesome, at least for joomla. I've configured memcached on some high trafficed joomla sites but it didn't work well, even I saw some slowness.
Then I let the xcache to make a chance and it did ! I've seen reduce of load average and increase the speed of page loading using xcache.

Here's how configure xcache 2.x on centos 6.x.
Don't forget to :
- set a password for xcache-admin
- check the right module path in xcache.ini (zend_extension=/usr/lib/php/modules/xcache.so or zend_extension=/usr/lib64/php/modules/xcache.so)



yum install php-devel -y
cd /usr/src
wget http://xcache.lighttpd.net/pub/Releases/2.0.1/xcache-2.0.1.tar.gz
tar -zxf xcache-2.0.1.tar.gz
cd xcache-2.0.1
phpize --clean && phpize
./configure --enable-xcache --enable-xcache-optimizer
chown -R nobody /usr/src/xcache-2.0.1
sudo -u nobody make
make install
echo -e "[xcache-common]" > /etc/php.d/xcache.ini
echo -e "zend_extension=/usr/lib64/php/modules/xcache.so" >> /etc/php.d/xcache.ini
echo -e "[xcache.admin]" >> /etc/php.d/xcache.ini
echo -e "xcache.admin.enable_auth = Off" >> /etc/php.d/xcache.ini
echo -e "[xcache]" >> /etc/php.d/xcache.ini
echo -e "xcache.shm_scheme =        \"mmap\"" >> /etc/php.d/xcache.ini
echo -e "xcache.size  =               64M" >> /etc/php.d/xcache.ini
echo -e "xcache.count =                 1" >> /etc/php.d/xcache.ini
echo -e "xcache.slots =                8K" >> /etc/php.d/xcache.ini
echo -e "xcache.ttl   =                 0" >> /etc/php.d/xcache.ini
echo -e "xcache.gc_interval =           0" >> /etc/php.d/xcache.ini
echo -e "xcache.var_size  =            32M" >> /etc/php.d/xcache.ini
echo -e "xcache.var_count =             1" >> /etc/php.d/xcache.ini
echo -e "xcache.var_slots =            8K" >> /etc/php.d/xcache.ini
echo -e "xcache.var_ttl   =             0" >> /etc/php.d/xcache.ini
echo -e "xcache.var_maxttl   =          0" >> /etc/php.d/xcache.ini
echo -e "xcache.var_gc_interval =     300" >> /etc/php.d/xcache.ini
echo -e "xcache.readonly_protection = Off" >> /etc/php.d/xcache.ini
echo -e "xcache.mmap_path =    \"/dev/zero\"" >> /etc/php.d/xcache.ini
echo -e "xcache.coredump_directory =   \"\"" >> /etc/php.d/xcache.ini
echo -e "xcache.experimental =        Off" >> /etc/php.d/xcache.ini
echo -e "xcache.cacher =               On" >> /etc/php.d/xcache.ini
echo -e "xcache.stat   =               On" >> /etc/php.d/xcache.ini
echo -e "xcache.optimizer =           On" >> /etc/php.d/xcache.ini
echo -e "[xcache.coverager]" >> /etc/php.d/xcache.ini
echo -e "xcache.coverager =          Off" >> /etc/php.d/xcache.ini
echo -e "xcache.coveragedump_directory = \"\"" >> /etc/php.d/xcache.ini
# Check the admin page : http://localhost/xcache-admin/index.php
cp admin /var/www/xcache-admin -R

[Tutorial] How optimize images JPG/PNG/GIF on Linux using littleutils package centos 7.x

Littleutils package contains couple of little utils useful for production websites.
I've used the opt-png, opt-jpg, opt-gif to reduce and optimize the size of images on some high trafficed websites without any quality loss.

# Install pngcrush :
cd /usr/src
wget https://sourceforge.net/projects/pmt/files/pngcrush/1.8.10/pngcrush-1.8.10.tar.gz
tar -zxf pngcrush-1.8.10.tar.gz
cd pngcrush-1.8.10
chown -R nobody /usr/src/pngcrush-1.8.10
sudo -u nobody make
cp pngcrush /usr/local/bin

On CentOS 7 you can use : yum install pngcrush

yum install libpng-devel gifsicle lzip libjpeg-turbo-utils lzma imlib2-devel zlib-devel 
cd /usr/src
wget http://downloads.sourceforge.net/project/littleutils/littleutils-source/1.0.39/littleutils-1.0.39.tar.bz2
tar -jxf littleutils-1.0.39.tar.bz2
cd littleutils-1.0.39
./configure
chown -R nobody /usr/src/littleutils-1.0.39
sudo -u nobody make
make install
make install-extra

The following script first backup all images in the /home folder, then optimize each one :


#!/bin/bash
SAVEIFS=$IFS
IFS=$(echo -en "\n\b")
cd /home;
NOW=$(date +"%d-%m-%Y");
echo -e "Backup images ...\nBackup file : ./backup-pictures-$NOW.tar";
`find . -regextype posix-extended -iregex "(.*?)\.(gif|jpe?g|png)" -print | tar -cf backup-pictures-$NOW.tar -T -`;
echo "" > log;
echo -e "Backup size is :";
echo `du -hs ./backup-pictures-$NOW.tar`;
echo -e "\nStart optimizing images ...\nLog file: ./log"
pics=`find . -regextype posix-extended -iregex "(.*?)\.(gif|jpe?g|png)"`;
for pic in $pics; do
        type=`file "$pic" | awk '{print $2}' | tr '[:upper:]' '[:lower:]'`;
        case $type in
                        "gif" )
                                        opt-gif "$pic" >> log
                                        ;;
                        "png" )
                                        opt-png "$pic" >> log
                                        ;;
                        "jpeg" )
                                        opt-jpg "$pic" >> log
                                        ;;

                        *)
                                        echo -e "file $pic which has type $type is undefined" >> log

                                        ;;
        esac
done
IFS=$SAVEIFS