Try waiting a few minutes and reloading.
(Cannot access the database: No such file or directory (localhost))
Backtrace:
#0 /var/www/wiki/includes/db/LoadBalancer.php(842): DatabaseBase->reportConnectionError('No such file or...') #1 /var/www/wiki/includes/db/LoadBalancer.php(537): LoadBalancer->reportConnectionError() #2 /var/www/wiki/includes/GlobalFunctions.php(3639): LoadBalancer->getConnection(0, Array, false) #3 /var/www/wiki/includes/page/WikiPage.php(366): wfGetDB(-1) #4 /var/www/wiki/includes/page/WikiPage.php(449): WikiPage->loadPageData() #5 /var/www/wiki/includes/page/WikiPage.php(491): WikiPage->exists() #6 /var/www/wiki/includes/page/WikiPage.php(215): WikiPage->getContentModel() #7 /var/www/wiki/includes/page/WikiPage.php(201): WikiPage->getContentHandler() #8 /var/www/wiki/includes/actions/Action.php(96): WikiPage->getActionOverrides() #9 /var/www/wiki/includes/actions/Action.php(151): Action::factory('view', Object(WikiPage), Object(RequestContext)) #10 /var/www/wiki/includes/MediaWiki.php(150): Action::getActionName(Object(RequestContext)) #11 /var/www/wiki/includes/MediaWiki.php(630): MediaWiki->getAction() #12 /var/www/wiki/includes/MediaWiki.php(508): MediaWiki->main() #13 /var/www/wiki/index.php(41): MediaWiki->run() #14 {main}