Memcached is a software that implements a RAM caching service based on a hash table.
You can also install this application at one-click checkout
Detailed description of this One-Click-Apps
Memcached is a server that stores some data in RAM with a specified lifetime. The data is accessed by a key (name). You can think of Memcached as a hash table stored on the server. It's mostly used to cache web page code, database query results, etc.
For starters, let's update the OS:
# yum update
After updating, perform a memcached installation:
# yum install memcached
Setting up memcached
Let's edit the file:
$ vim /etc/sysconfig/memcached
Make sure that this configuration file has the following lines:
PORT="11211" USER="memcached" MAXCONN="256" CACHESIZE="64" OPTIONS="-l 127.0.0.1"
PORT 11211 is the default listening port for Memcached.
USER is the memcached user from which the daemon will run.
MAXCONN - the maximum number of possible connections.
CACHESIZE is the number of megabytes (64 MB) to use if you have a lot of traffic, this is good for most small/medium sites. For a busy server, you can increase it by 512 or 1 GB (1024 MB).
OPTIONS="-l 127.0.0.1″ - this means memcached will only listen on localhost, avoiding any external connections. It is set to INADDR_ANY by default
Memcached is running:
# systemctl enable memcached # systemctl start memcached
Installing PHP extensions with memcached.
# yum install php-pear pecl_http php-devel
And we execute:
$ pecl install memcache
If PECL asks you the question you see below when installing, just press ENTER:
"Enable memcache session handler support? [yes]"
If your server has php-fpm installed, then to restart it, run:
# service php-fpm reload
If you have apache installed on your server, then to restart it, execute:
# systemctl restart httpd
Checking MemCache configuration
Use the following command to test and verify that the Memcached service is working properly:
$ echo "stats settings" | nc localhost 11211
Now we need to check if the extension is enabled and make sure it works correctly. Create a file in your home directory and write the following PCP code:
# echo "<?php phpinfo(); ?>" > /var/www/html/php_info.php
Configuring the firewall for Memcached
Add the following rules to allow connections (for memcached to work):
iptables -A INPUT -p tcp --destination-port 11211 -m state --state NEW -m iprange --src-range 192.168.1.10-192.168.1.15 -j ACCEPT iptables -A INPUT -p udp --destination-port 11211 -m state --state NEW -m iprange --src-range 192.168.1.10-192.168.1.15 -j ACCEPT
Check if the memcached daemon is running on the OS:
$ ps -aux | grep memcached