ES master: srv101: yum install mysql-server add these lines to /etc/my.cnf [mysqld] section: log-bin server-id=1002101 skip-name-resolve key_buffer_size=100M Run: # chkconfig mysqld on # service mysqld start Write down: # mysql -e 'show master status' +-------------------+----------+--------------+------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | +-------------------+----------+--------------+------------------+ | srv101-bin.000003 | 4155 | | | +-------------------+----------+--------------+------------------+ # mysql < ~midom/php/maintenance/ourusers.sql # mysql -e "GRANT REPLICATION SLAVE ON *.* TO repl@10.0.2.101 IDENTIFIED BY '$(<repl-password)'" # mysql -e "GRANT REPLICATION SLAVE ON *.* TO repl@10.0.2.102 IDENTIFIED BY '$(<repl-password)'" # mysql -e "GRANT REPLICATION SLAVE ON *.* TO repl@10.0.2.103 IDENTIFIED BY '$(<repl-password)'" ES slave: srv102 yum install mysql-server add these lines to /etc/my.cnf [mysqld] section (only ID differs): log-bin server-id=1002102 skip-name-resolve key_buffer_size=100M # chkconfig mysqld on # service mysqld start # mysql -e "CHANGE MASTER TO MASTER_HOST='srv101',MASTER_USER='repl',MASTER_PASSWORD='$(<repl-password)',MASTER_LOG_FILE='srv101-bin.000003', MASTER_LOG_POS=4155 " Same on srv103, just change the ID. Then on zwinger: # cd ~/midom/php/maintenance/storage # ./make-all-blobs srv101 In case of properly running replication, this command on zwinger should work: # sql -h srv103 -e 'show create table blobs \G' enwiki *************************** 1. row *************************** Table: blobs Create Table: CREATE TABLE `blobs` ( `blob_id` int(10) unsigned NOT NULL auto_increment, `blob_text` longblob, PRIMARY KEY (`blob_id`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 MAX_ROWS=1000000 AVG_ROW_LENGTH=1000000 Add these lines to db.php: 'cluster17' => array( '10.0.2.101' => 1, '10.0.2.102' => 1, '10.0.2.103' => 1, ), Add or replace old cluster in: $wgDefaultExternalStore = array( 'DB://cluster17');