Memcached Sessions

In a clustered environment, PHP sessions need to be shared. Here are steps to enable sessions stored in memcache.

Install memcached

yum install memcached
/etc/init.d/memcached start

NOTE: edit /etc/sysconfig/memcached and set appropriate config values

yum install php-devel
pecl install memcache
echo "extension=memcache.so" > /etc/php.d/memcache.ini
/etc/init.d/httpd restart

NOTE: The following patch can be applied to the deki /trunk branch

wget -O /tmp/memcache.patch http://www.mindtouch.com/~petee/memcache.patch
cd /var/www/dekiwiki
patch -p0 < /tmp/memcache.patch

To enable memcached sessions, you'll need to define two variables in LocalSettings.php

$wgSessionsInMemcached = true;

$wgMemCachedServers = array( 'tcp://127.0.0.1:11211?persistent=1&weight=1&timeout=1&retry_interval=15');

NOTE: multiple memcache servers can be used by adding multiple entries to the $wgMemCachedServers arary.

To ensure that sessions are being stored in memcache, enable verbose logging by setting the following in /etc/sysconfig/memcached

OPTIONS="-vv"

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