Case study: Organic groups intranet with LDAP authentication and performance tuning (Xhprof, Varnish)
Success story of Riga East Clinical University Hospital homepage and intranet Drupal 7 development/optimisation.
Stats: 80k homepage visits every month and 550 active intranet users.
Technologies used: Nginx, Varnish, Apache, Apache Solr, Winbind, APC
Tools used: Xhprof, Apache benchmark, mysqltuner.pl, Mytop
Some modules: Organic groups, Rules, Revisioning, tons of custom modules...
Some functionality: Automatic LDAP authentication, room/inventory reservation system, absence calendar, access control delegation to certain branches of website...