DocuWiki prints out lots of warning information like “Strict Standards: Declaration of …”

Solution 1: You may be able to set this in .htaccess, however some hosts may not respect the setting in .htaccess
See this reference.

Solution 2: Reduce the error reporting in php.ini e.g. “error_reporting = E_ALL & ~E_NOTICE”
See here.

/usr/bin/php: error while loading shared libraries: libXau.so.6: failed to map segment from shared object: Cannot allocate memory

Caused by: Did you try to update memory settings in php config? Seems if you do this, you also need to increase the amount available to Apache, i.e.

vi /usr/local/apache/conf/httpd.conf

And set the RLimitMEM to something like 651048618

See this reference.