Thread:Extension talk:LDAP Authentication/LDAP Authentication + Apache2 High CPU Usage/reply (3)

Your configuration isn't including LdapAutoAuthentication, and even if it was, it isn't configured to use it. That isn't causing your problem.

For APC, I don't mean the MediaWiki extension, I mean the PECL/PEAR extension for PHP. APC stands for Alternative PHP Cache. It speeds up PHP by quite a bit. Here are ubuntu instructions:

http://baheyeldin.com/technology/linux/installing-php-apc-on-ubuntu-dapper-and-debian.html

You aren't using memcached according to that configuration. You don't necessarily need to though. If you get APC working, and you aren't using multiple apache servers, you can use APC in place of memcached. Set:

$wgMainCacheType = CACHE_ACCEL; $wgParserCacheType = CACHE_ACCEL; $wgMessageCacheType = CACHE_ACCEL;

If you ever have multiple servers for apache, you'll want to use memcached instead. To use memcached, you'll need to install the server, and then point your configuration to the server. In ubuntu, you can install it the following way:

apt-get install memcached /etc/init.d/memcached start

If you continue to have issues, you may want to turn on the LDAP debug logs, and see what activity you are getting when users are browsing around and not logging in.