A slow OpenCart is one of the most common complaints store owners have. One of the most effective ways to speed it up is Redis. Here it is, step by step.
Why Redis rather than file cache
Stock OpenCart uses a file cache in storage/cache/. Redis holds data in RAM, which is 10–100× faster to read than disk. The difference is especially clear on stores with 1,000+ products.
Step 1: install Redis
apt install redis-server php8.3-redis systemctl enable --now redis-server
Check that Redis is listening on localhost:
redis-cli ping # PONG
Step 2: configure redis.conf
maxmemory 256mb maxmemory-policy allkeys-lru bind 127.0.0.1 requirepass your_strong_password
Step 3: connect it to OpenCart
In config.php, change the storage driver:
define('CACHE_DRIVER', 'redis');
define('CACHE_HOSTNAME', '127.0.0.1');
define('CACHE_PORT', 6379);
define('CACHE_PASSWORD', 'your_strong_password');
Step 4: move sessions to Redis
In php.ini or the PHP-FPM pool configuration:
session.save_handler = redis session.save_path = "tcp://127.0.0.1:6379?auth=your_strong_password"
Monitoring the hit rate
redis-cli info stats | grep keyspace_hits redis-cli info stats | grep keyspace_misses
Target: a hit rate above 90%. Below that, raise maxmemory.
The result
Configured properly, Redis brings TTFB down from 800–1500 ms to 50–150 ms, and cuts load on MariaDB by 40–70%.
Want me to set up Redis for your OpenCart? Get a quote.
