Redis can enhance the performance of (busier) CraftCMS website and shops. We recommand a configuration as following, which will use redis for caching and a redis persistent instance for the sessions (over unix socket files).
More info here about the Redis setup: https://portal.hosted-power.com/knowledgebase/article/112/redis-server/
Add redis caching component
composer require --prefer-dist yiisoft/yii2-redis
Modify config/app.php
[
...
'components' => [ 'class' => yii\redis\Cache::class, 'defaultDuration' => 86400, 'redis' => [ 'unixSocket' => '/var/run/redis/redis.sock', 'database' => 1, ], ], 'session' => [ 'class' => yii\redis\Session::class, 'as session' => [ 'class' => \craft\behaviors\SessionBehavior::class, ], 'redis' => [ 'unixSocket' => '/var/run/redis-persistent/redis.sock', 'database' => 1, ], ], ], ] ...