To enable Memcached on your website hosted by Cloud Platform, you must install the Memcache API and Integration module in your codebase, and configure the module for use.
When configuring your website to use Memcached, be aware of the following considerations:
- Do not edit the
memcache_key_prefix
ormemcache_servers
settings, as Cloud Platform adds the correct values in Acquia-specific code defined by the Acquia require line, or otherwise available by default on Cloud Next. Altering these values can cause unexpected behavior. - If your website uses either automated testing or the
memcache_admin
submodule, you must enable the Memcache API and Integration module. Although the current Drupal version does not require you to enable the module, Acquia recommends you to enable the module to receive notifications about module updates. - For more information about stampede protection and database locking, see Enabling stampede protection and moving locks into memory.
Configuration for the current Drupal version
For Memcached to function, you must provide additional configuration code that enables autoloading, and identifies Memcached as an alternative cache back-end.
To configure your website for Memcached, make the following changes to your codebase, depending on your subscription type:
For environments running on Cloud Next technologies:
Memcache runs per-environment instead of per-server and leverages mcrouter. Steps 2 and 3 are not required because Memcache configuration logic is included automatically. To exclude this logic on your environments, add the following line to your
settings.php
file:define('AH_NO_MEMCACHE_INCLUDE', 1);
- If you have the older
cloud-memcache-d8+.php
file stored in this repository, ensure that you delete it.
Download the Memcache API and Integration module, and then add the module to your codebase in the
modules/contrib/memcache
directory. We recommend to use Composer to install the module:composer require drupal/memcache
Add the composer package that contains the Acquia Memcache settings to your project:
composer require acquia/memcache-settings
For each website that requires Memcached, edit the Cloud Platform database require line in
settings.php
with a PHPrequire_once
statement, similar to the following example:if (file_exists('/var/www/site-php')) { require('/var/www/site-php/mysite/mysite-settings.inc'); // Memcached settings for Acquia Hosting $memcache_settings_file = DRUPAL_ROOT . "/../vendor/acquia/memcache-settings/memcache.settings.php"; if (file_exists($memcache_settings_file)) { require_once $memcache_settings_file; } }
Rebuild caches by running the following command, replacing
[example.com]
with the domain name of your website:drush cr --uri=[example.com]
- Truncate all
cache_
tables in the database for the website.
Memcache is now enabled for your website. Continue to read the next section.
If you need assistance, create a Support ticket.
Download the Memcache API and Integration module and add the module to your codebase in the
modules/contrib/memcache
directory. We recommend to use Composer to install the module:composer require drupal/memcache
- Download
acsfd8+.memcache.settings.php
, and then add it to thefactory-hooks/post-settings-php
directory. For more information about the post-settings-php hook, see Altering values in settings.php with hooks. Rebuild caches by running the following command, replacing
[example.com]
with the domain name of your website:drush cr --uri=[example.com]
- Truncate all
cache_
tables in the database for the website.
Memcache is now enabled for your website. If you need assistance, create a Support ticket.
Configuration for Drupal 7
If you are installing the module on a Drupal 7 website, you must enable the module before modifying settings.php
, or you will receive a ServiceNotFoundException:
error message.
To configure your Drupal 7 website for Memcached, make the following changes to your codebase, depending on your subscription type:
- Download the Memcache API and Integration module, and then add the module to your codebase in the
sites/all/modules/contrib/memcache
directory. - Download
cloud-memcache-d7.php
, and add the contents of the file to your website’ssettings.php
file, after the Acquia database require line. Clear caches by running the following command, replacing
[example.com]
with the domain name of your website:drush cc all --uri=[example.com]
- Truncate all
cache_
tables in the database for the website.
Memcache is now enabled for your website. If you need assistance, create a Support ticket.
- Download the Memcache API and Integration module, and then add the module to your codebase in the
sites/all/modules/contrib/memcache
directory. - Download
acsfd7.memcache.settings.php
, and add it to thefactory-hooks/post-settings-php
directory. For more information about the post-settings-php hook, see Altering values in settings.php with hooks. Edit the file, modifying the following lines if they do not correspond to the location of the Memcache API and Integration module in your codebase:
$conf['cache_backends'][] = 'sites/all/modules/contrib/memcache/memcache.inc'; $conf['lock_inc'] = 'sites/all/modules/contrib/memcache/memcache-lock.inc';
Clear caches by running the following command , replacing
[example.com]
with the domain name of your website:drush cc all --uri=[example.com]
- Truncate all
cache_
tables in the database for the website.
Memcache is now enabled for your website. Continue to read the next section.
If you need assistance, create a Support ticket.
Allocating memory to Memcached
For environments running on Cloud Next technologies, you can adjust the memory allocated to Memcached as follows:
Sign in to the Cloud Platform user interface and select your application and environment.
Click Actions > Configure Environment.
Click Advanced.
Scroll to the bottom of the page and select Memcached.
You must have at least 512 MB in Memcached. However, for enhanced performance, Acquia recommends that you have 1 GB for Drupal 10 applications.
Click Save.
For environments running on the Cloud Classic infrastructure, you must create a Support ticket to request that your Memcached memory allocation be modified. Larger amounts of memory can be allocated to Cloud Classic environments with dedicated Memcached infrastructure. Contact your Acquia account team for more information about this advanced configuration.
Using binary protocol
You can leverage the Memcache binary protocol in Cloud Classic environments. However, Acquia does not recommend its use.
To use this protocol in Cloud Classic environments, ensure that you enable the Memcached::OPT_TCP_NODELAY
flag in Memcache options to avoid slow fetches of empty cache items.
The Memcache binary protocol is not supported in Cloud Next environments. Cloud Next leverages mcrouter, which only supports the ASCII protocol for Memcache. If you enable binary protocol in Cloud Next environments, Drupal and PHP cannot communicate with Memcache servers. Therefore, the application fails to set or get cache items but does not return an error message.