How to Enable Persistent Object Cache using Redis on WordPress

The Redis is the type of cache solution for Persistent Object Cache for WordPress. It is only recommended solution for object cache. This type of cache stores data from database queries into a memory for fast access of data. It works so effectively with relational databases service like MySQL, MariaDB etc.

When WordPress page is loaded it perform database queries to retrieve information. It requires some time to perform database queries. By default Redis performed to store that database queries into a memory. So that the page load time slight deceases hence you will get fast page loading times. You need to follow all the details so carefully to integrate the Redis object cache on your WordPress instances.

Step-1 : Install the Redis packages

$ sudo apt install redis-server php-redis

Step-2 : Check that Redis is working or not

$ sudo redis-cli

Type the given command

127.0.0.1:6379> ping

Sample Output

127.0.0.1:6379> PONG

This means Redis works.

Now type exit to exit from Redis-cli.

Step-3 : Setup max memory and its rules for Redis

$ sudo vi /etc/redis/redis.conf

Find the given lines.

# maxmemory

replace it with given parameter.

maxmemory 256mb

When all edit done then :wq to save and exit.

Restart the services to make changes in effect.

$ sudo systemctl restart redis-server

Step-4 : Add Redis cache to WordPress configuration file

Now edit wp-config.php file and add these lines to the last of the file.

define( 'WP_CACHE', true );
define( 'WP_CACHE_KEY_SALT', 'techbrown.com' );

After that save and exit.

Step-5 : Enable Redis object cache to your WordPress

Finally you need to install the WordPress plugin – Redis Object Cache By Till Kruss to enable the Redis object cache. After installation of plugin now you are ready to use the flush cache option from above plugin settings. To enable the Redis on your website.

Congratulations now you have configured the Redis Object cache for WordPress CMS.