I've just created a free account on Acquia to test Drupal Commons.
I followed the instructions (see https://docs.acquia.com/commons/install/acquia-cloud and https://docs.acquia.com/cloud/performance/memcached) to configure Drupal Commons.
As the memcache module is already included in the distribution, I only added at the bottom of my settings.php the following code:
# configuration for Drupal Commons on Acquia Cloud
# see https://docs.acquia.com/cloud/performance/memcached
$conf['cache_backends'] = './profiles/commons/modules/contrib/memcache/memcache.inc';
$conf['cache_default_class'] = 'MemCacheDrupal';
$conf['cache_class_cache_form'] = 'DrupalDatabaseCache';
# see https://docs.acquia.com/commons/install/acquia-cloud
# the following line was commented out because $conf['cache_class_cache_form'] it's already defined above
#$conf['cache_class_cache_form'] = 'DrupalDatabaseCache';
But now I get this error in every page:
User error: Failed to connect to memcache server: 127.0.0.1:11211 in dmemcache_object() (line 415 of /path-to-docroot/profiles/commons/modules/contrib/memcache/dmemcache.inc).
What did I miss? Any idea on how I could get rid of it?