Install memcached with libmemcached for php5-fpm

Memcached is useful for speeding up php sites like WordPress or interfaces like ownCloud. Memcached can be installed with libmemached support which is a C and C++ compiler which greatly speeds up processing for the cache. This guide assumes you are using php5-fpm with nginx or apache2 on Debian or Ubuntu/Lubuntu. This guide was tested on a Raspberry Pi 2, Banana Pi and Orange Pi. I made this tutorial because I noticed ownCloud guides using nginx recommend installing memcached but it is never actually enabled. It is also part of my VPS migration plans when I migrate my DigitalOcean 512MB droplet to a 1GB droplet to host the new forum.

Install memcached with libmemcached

Install some dependencies like memcached, php5-dev tools and php-pear for installing extensions, libsasl2-dev is optional and may be important for shared hosting users. I haven't tested SASL because I use a DigitalOcean VPS for hosting this site.

Install these packages to get memcached up and running quickly, for those who want the latest version there are instructions for building libmemcached and the latest memcached.

sudo apt-get update
sudo apt-get install libmemcached-tools memcached libsasl2-dev php5-dev php-pear pkg-config build-essential -y

If you are on php 7 install pear manually

wget http://pear.php.net/go-pear.phar
php go-pear.phar

If you do not want the latest libmemcache, you can now skip down to adding the correct extension lines to the php5-fpm php.ini file.

Build libmemcached

You can build the absolute latest libmemcached by following these steps.

Download the libmemcached source file (there may be an updated version on the official page), unpack it and enter the directory

mkdir ~/libmemcacheinstall
wget https://launchpad.net/libmemcached/1.0/1.0.18/+download/libmemcached-1.0.18.tar.gz
tar -xvf libmemcached-1.0.18.tar.gz --strip-components 1 -C ~/libmemcacheinstall
cd ~/libmemcacheinstall

If you do want SASL support use this command to configure libmemcached

./configure --prefix=/usr

If you don't need SASL support configure libmemcached with this syntax (source)

./configure --prefix=/usr --disable-memcached-sasl

Get the number of cores you are working with on your system so you can build libmemcached with all your CPU cores

nproc

The virtual machine I am running uses 2 cores so add this after the -j to compile libmemcached with both cores and then make install to install it

make -j2
make install

Install memcached pecl extension

Using php-pear's installer to install memcached, run this command

pecl install pecl_http-2.5.5 memcached

You will be prompted for the location of libmemcached, just press Enter and it should find it automatically, if not enter /usr/local

Now you need to add a line to enable memcached support in your php.ini.

This command appends the line to the bottom of the php.ini file for php5-fpm

echo "extension=memcached.so" >> /etc/php5/fpm/php.ini

Restart php5-fpm

service php5-fpm restart

If you ever need to uninstall memcached

pecl uninstall memcached

You can remove the libmemcached build folder from your home directory

rm -R ~/libmemcacheinstall

Test memcached with libmemcached is Enabled

Time to test that memcached with libmemcached is installed for php5-fpm on nginx or apach2. I will assume you already have WordPress or some other frontend that uses php.

For nginx or apach2 create an info.php file in your root directory for the virtual host that serves php

nano /var/www/info.php

Paste this code

<?php
phpinfo();
?>

Ctrl+X, Y and Enter to save

Browse to the info.php file at http://ip.address/info.php

You will see a memcached section like this if you scroll down

Benchmarking memcached

If you want you can do a quick memcached benchmark

memslap --server=127.0.0.1 --concurrency=2 --execute-number=50

You may see memslap command not found in which case use

memcslap --server=127.0.0.1 --concurrency=2 --execute-number=50

Output

Threads connecting to servers 2
Took 0.015 seconds to load data

That concludes the install memcached with libmemcached for php5-fpm for nginx or Apache web servers.