🧠 Memcached & Redis Installation Guide for cPanel (AlmaLinux 9 / CloudLinux 9)

Here is a complete guide for installing and configuring Memcached and Redis on cPanel running AlmaLinux 9 or CloudLinux 9, tailored for server optimization and performance enhancement.

🔧 Step 1: Enable EPEL Repository

yum install epel-release -y

This allows access to additional packages like Redis and Memcached not available in the base repos.

🔁 Step 2: Install and Configure Redis

yum install redis -y

Start and Enable Redis

systemctl start redis
systemctl enable redis

Check Redis Status

systemctl status redis

You should see Active: active (running) if Redis is working properly.

Benchmark Redis

Optional, but useful for a quick performance test:

redis-benchmark -q -n 1000

💾 Step 3: Install Memcached

yum install memcached -y

Start Memcached

systemctl start memcached
systemctl enable memcached

Check Memcached Status

systemctl status memcached

You should see Active: active (running) if Memcached is working.

⚙️ Step 4: Configure Memcached

Edit the configuration file:

nano /etc/sysconfig/memcached

Replace or confirm the following values:

PORT="11211"
USER="memcached"
MAXCONN="1024"
CACHESIZE="64"
OPTIONS="-l 127.0.0.1 -U 0"

Explanation:

-l 127.0.0.1 restricts Memcached to localhost (secure).

-U 0 disables UDP (recommended for security).

Adjust CACHESIZE depending on available RAM.

Restart Memcached to apply changes:

systemctl restart memcached

🔐 Notes for cPanel Servers

These services do not interfere with cPanel or WHM.
For PHP-based applications (e.g., WordPress, Magento), make sure to install corresponding PHP extensions: yum install ea-phpXX-php-pecl-redis ea-phpXX-php-pecl-memcached Replace XX with your desired PHP version (e.g., 81).

You can verify extensions are loaded using:

php -m | grep -E 'redis|memcached'

✅ Final Checklist

Task	Status
EPEL installed	✅
Redis installed & running	✅
Memcached installed & running	✅
Memcached config updated	✅
PHP extensions installed	✅