Master/Slave

The following setup has one master and two slaves with cross failover. If master fails, system will continue in read-only mode. If both slaves fail, system will continue only using the master.

<?php
$databases['default']['master'] = array (
  'database' => 'mydatabase',
  'username' => 'readwrite',
  'password' => 'readwrite',
  'host' => 'master',
  'port' => '',
  'driver' => 'mysql',
  'prefix' => '',
);
$databases['default']['slave'][] = array (
  'database' => 'mydatabase',
  'username' => 'readonly',
  'password' => 'readonly',
  'host' => 'slave1',
  'port' => '',
  'driver' => 'mysql',
  'prefix' => '',
  'readonly' => TRUE,
);
$databases['default']['slave'][] = array (
  'database' => 'mydatabase',
  'username' => 'readonly',
  'password' => 'readonly',
  'host' => 'slave2',
  'port' => '',
  'driver' => 'mysql',
  'prefix' => '',
  'readonly' => TRUE,
);

$databases['default']['default'] = array (
  'driver' => 'autoslave',
  'master' => array('master', 'slave'),
  'slave' => array('slave', 'master'),
);
?>