Redis Installation
Add repo which maintains latest redis
add-apt-repository ppa:chris-lea/redis-server
Install redis-server and php-binding
apt-get update
apt-get install redis-server php5-redis
WordPress Object Cache
We are using this object-cache plugin – https://github.com/alleyinteractive/wp-redis
cd /var/www/example.com/htdocs/wp-content
wget https://raw.githubusercontent.com/alleyinteractive/wp-redis/master/object-cache.php
chown www-data: object-cache.php
WordPress Cache Salt/Prefix
Useful if you have multiple WordPress.
Inside wp-config.php
define('WP_CACHE', true);
define('WP_CACHE_KEY_SALT', 'example.com/subdir');
Related: https://rtcamp.com/tutorials/php/redis-php-sessions/