WordPress has built-in object caching but, object cache is non-persistent by default. This means that data stored in the cache resides in memory only and only for the duration of the request. Powered Cache comes with several different object cache backend to saving persistent.
Requirements: A Memcached server and the PECL Memcache extension.
Memcache Backend uses 127.0.0.1 as the default Memcached server. If you want to use a different server, small modifications are needed.
Add something similar to the following to wp-config.php
$memcached_servers = array( 'default' => array( '10.10.10.20:11211', '10.10.10.30:11211' ) );
if you want to separate caching by group try something like;
$memcached_servers = array( 'default' => array( '10.10.10.20:11211', '10.10.10.30:11211' ), 'options' => array('10.10.10.40:11211');
The same configuration with Memcache, the only difference is, it uses the “Memcached” extension of PHP, not Memcache.
Requirements: Redis server and phpredis extension.
edit wp-config.php to add your Redis credentials (authentication is turned off by default, you can add ‘auth’ key and value if needed)
$redis_server = array( 'host' => '127.0.0.1', 'port' => 6379, 'database' => 0 );
For more detail about object caching: https://codex.wordpress.org/Class_Reference/WP_Object_Cache
Object Cache on Multisite
Object cache works perfectly well with WordPress multisite, however, Powered Cache doesn’t display the object cache options when the plugin is not activated network-wide. Because site options suppose to control only a single site, not the entire network which conflicts with object cache fundamentals.