Enable memcached on Magento 2 in Plesk Server

To install memcached, run

apt install php-memcached
apt install build-essential
apt install autoconf automake gcc libmemcached-dev libhashkit-dev pkg-config plesk-php*-dev zlib1g-dev

Enable memcached php module

/opt/plesk/php/7.3/bin/pecl install memcached

This is for PHP 7.3, change the path to pecl for your version of PHP.

Activate memcached

echo "extension=memcached.so" > /opt/plesk/php/7.3/etc/php.d/memcached.ini

Update php handler

plesk bin php_handler --reread

Restart php-fpm

systemctl stop plesk-php73-fpm.service
systemctl start  plesk-php73-fpm.service

Install memcached deamon

apt install memcached

Restart memcached

systemctl enable memcached
systemctl restart memcached

Verify it is working with netstat

malta2032:~# netstat -lntp | grep mem
tcp        0      0 127.0.0.1:11211         0.0.0.0:*               LISTEN      30204/memcached     
malta2032:~# 

Activate memcached in Magento 2

Edit file

vi app/etc/env.php

Find

    'session' => [
        'save' => 'files'
    ],

Replace with

    'session' => [
        'save' => 'memcached',
        'save_path' => '127.0.0.1:11211'
    ],

If you get error like

Warning: SessionHandler::read(): open(127.0.0.1:6379/sess_0s39482mnk2hhoflf4d6odjuv2, O_RDWR) failed: No such file or directory (2) in /vendor/magento/framework/Session/SaveHandler/Native.php on line 22

edit your php.ini and set “session.save_handler” from “files” to “memcached”.

See if memcached working

To see if memcached is caching, you can use

telnet 127.0.0.1  11211
stats items

To exit, type

quit

See Magento, Memcached