Install Memcache

[Rynn Bronaugh]

Memoryobject caching systems like Memcached can optimize backend database performance by temporarily storing information in memory, retaining frequently or recently requested records. In this way, they reduce the number of direct requests to your databases.

You can also install libmemcached-tools, which is a package that contains various tools that you can use to examine, test, and manage your Memcached server. Add the package to your server with the following command:

First, ensure that your Memcached instance is listening on the local IPv4 loopback interface 127.0.0.1. The current version of Memcached that ships with Ubuntu and Debian has its -l configuration parameter set to the local interface, which means that it is configured to only accept connections from the server where Memcached is running.

Note that if you would like to disable IPv4 support and only listen for IPv6 connections, you can remove the -l 127.0.0.1 line from /etc/memcached.conf and restart the service using the systemctl command.

If you would like to use Memcached with Unix Domain Sockets, you can enable this support by editing the /etc/memcached.conf configuration file. Note that if you configure Memcached to use a Unix Domain Socket, Memcached will disable TCP and UDP support so be sure that your applications do not need to connect using those protocols before enabling socket support.

To get started adding SASL support, you will need to install the sasl2-bin package, which contains administrative programs for the SASL user database. This tool will allow you to create an authenticated user or users. Run the following command to install it:

In addition to specifying the logging level, mech_list is set to plain, which tells Memcached that it should use its own password file and verify a plaintext password. The last line that you added specifies the path to the user database file that you will create next. Save and close the file when you are finished.

$? will always return the exit code of the last command that exited. Typically, anything besides 0 indicates process failure. In this case, you should receive an exit status of 1, which indicates that the memcstat command failed.

Running memcstat again, this time with a username and password will confirm whether or not the authentication process worked. Run the following command with your credentials substituted in place of the sammy and your_password` values if you used different credentials:

By default Memcached is only configured to listen on the local loopback (127.0.0.1) interface, which protects the Memcached interface from exposure to outside parties. However, there may be instances where you will need to allow access from other servers. In this case, you can adjust your configuration settings to bind Memcached to a private network interface.

Note: We will cover how to configure firewall settings using UFW in this section, but it is also possible to use DigitalOcean Cloud Firewalls to create these settings. For more information on setting up DigitalOcean Cloud Firewalls, see our Introduction to DigitalOcean Cloud Firewalls. To learn more about how to limit incoming traffic to particular machines, check out the section of this tutorial on applying firewall rules using tags and server names and our discussion of firewall tags.

Before you adjust your configuration settings, it is a good idea to set up firewall rules to limit the machines that can connect to your Memcached server. First you will need to record the private IP address of any machine that you would like to use to connect to Memcached. Once you have the private IP address (or addresses), you will add an explicit firewall rule to allow the machine to access Memcached.

Test connectivity from your external client to ensure that you can still reach the service. It is a good idea to also check access from a non-authorized client (try connecting without a user and password) to ensure that your SASL authentication is working as expected. It is also a good idea to try connecting to Memcached from a different server that is not allowed to connect to verify that the firewall rules you created are effective.

In this tutorial you explored how to configure Memcached with IPv4, IPv6, TCP, UDP, and Unix Domain Sockets. You also learned how to secure your Memcached server by enabling SASL authentication. Finally, you learned how to bind Memcached to your local or private network interface and how to configure firewall rules to limit access to Memcached.

Can I use both Memcache and Memcached php extensions on the same server at the same time? Just to be clear so you dont misunderstand what I mean by this question, here is my scenario: I have both Joomla and phpbb for my website. Joomla provides support for both memcached and memcache where as phpbb only provides support for memcache. So I am planning to do this:

When I set the memory limit for the memcached server to 512M in/etc/memcached.conf, does it mean that this memory limit is goingto be shared between both memcache and memcached extension? Thisshouldnt be a problem if say memcache uses more memory thanmemcached or vice versa? Do they both play nice to each other?

In the scenario like this, should I try to give preference to only 1php extension (like either memcache only in my case) to keep things simplewithout conflicts between the two or it shouldnt matter. What I meanis, if you say it is okay to use both (for Q1), then out ofprofessional practice, even if both can be used at the same time,should I still try to use the same php extension for both Joomla andphpbb if possible to minimize headaches? Would that make difference in any ways?

Memcached is a free and open-source distributed memory caching system that is often used to speed up dynamic web applications by caching data in memory. Installing Memcached on Ubuntu is a straightforward process.

By default, Memcached listens only on localhost (127.0.0.1) on port 11211. You can customize Memcached's configuration by modifying the /etc/memcached.conf file. For example, to increase the amount of memory allocated to Memcached from the default of 64MB to 256MB, you can modify the -m option as follows:

I was trying to follow the actual owncloud config guide, but the chaching using APCu seems kinda hand-wavy. I tried that first on a separate clean install but I never got it working either. It says that on PHP 5.5 and up APCU is installed and enabled by default, but I added the memcahce line to config.php and owncloud barfed and i got similar errors. That's when i went looking for a more complete how-to that had more detail on the caching setup.

I'm kinda new to web based programs and I wasn't familiar with the phpinfo() way of checking to see enabled modules. I will definitely check that out. Checking php aside, for the small, single server installations is there anything else you need to do to get APCu working, other than the one line in config.php?

Even if the small, single server installation doesn't recommend Redis as the memcache.locking i would also install this after you got APCu for memcache.local running (Also note the version requirement for redis on this page).

Memcached is an open source, high-performance, distributed memory object caching system. While it is generic in nature, it is intended for use in speeding up dynamic web applications by alleviating database load.

First and foremost, set up a firewall in your LAN if memcached servers should be accessible only from within your local network. Do not allow external traffic to ports used by memcached (e.g. 11211 as used by default).

If you are not required to use UDP for memcached, we highly recomment switching to TCP connections for your memcached server (add "-U 0" to the OPTIONS variable in /etc/sysconfig/memcached). If you do require the use of UDP and require remote access to memcached servers (for example, in a clustering scenario), it is recommended to configure a firewall to allow connections only from trusted hosts.

Note: It's possible to disable memcache session handler support. The 'pecl install' option prompts for this (default is enabled) however when compiling statically into PHP the --disable-memcache-session configure option may be used.

So after doing the installation steps and coping the obj file to wp-content the website was braking with the error message something about cannot find memcache.

WHM (cpanel) supports both memcache and memcached but has dropped support for memcache. Please note that memcached is supposedly better. So I did not have memcache installed. Only memcached. And I had the critical error.

Memcached is an open-source memory caching system that you can use to speed up web applications and dynamic websites. Memcached works by storing frequently accessed data in RAM hence reducing the time an application reads data from databases, files or API interfaces. If your website, web application or API server has high read calls and infrequent writes, Memcached can be a great tool for you.

Since its development in 2003, the technology has been very successful and is deployed by a number of great websites like LiveJournal. To use the Memcached technology, your code should support the technology. If you are a programmer, you can rewrite your program to take advantage of Memcached technology.

In this guide, we will take you through the steps of setting up a Memcached server on your Alibaba Cloud Elastic Compute Service (ECS) Ubuntu 18.04 instance and show you how you can use it on your PHP code to speed up operations.

Next, install PHP by running the command below. As with the previous step, you may skip installing PHP if it is already running on your system. The command below also installs libapache2-mod-php module that links Apache web server with PHP.

Since Memcached package is available on the default Ubuntu software repository, you will use apt to install it. You will also install libmemcached-tools . This is a set of lightweight library and tools used by the Memcached server.

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