Child pages
  • Database Load Balancing
Skip to end of metadata
Go to start of metadata

Imported from:

We are looking to have the ability to run In-Portal website in Database Load Balanced environment. It's usually necessary for high load/availability websites.

The idea is to have MASTER/SLAVE(s) configuration. This will separate WRITE/READ database requests between 2+ servers (1 Master and 1+ Slaves replicated from Master).

  1. all Admin requests go to MASTER
  2. all Front READ requests go to SLAVE
  3. all Front WRITE requests go to MASTER
  4. all Front Search READ go to MASTER

To enable load balancing:

  1. add $_CONFIG['Database']['LoadBalancing'] = '1'; to /system/config.php file
  2. create /system/db_servers.php file with following content: 

    $_CONFIG['Databases'] = Array ( 
        Array ( 
            'DBHost' => 'slave.host1', 
            'DBUser' => 'slave.user1', 
            'DBUserPassword' => 'slave.user.password1', 
            'DBLoad' => 1, 
        Array ( 
            'DBHost' => 'slave.host2', 
            'DBUser' => 'slave.user2', 
            'DBUserPassword' => 'slave.user.password2', 
            'DBLoad' => 1, 
            'DBMaxLag' => 15, // optional, slave replication delay in seconds 
            'DBMaxThreads' => 100, // optional, when slave thread count is above this number, then it won't be used 
  3. only Slave Servers are listed in file above, since database server defined in /system/config.php is considered as Master Server for backwards compatibility. 

See$wgDBservers for more details.

Most likely this functionality will be added to In-Portal 5.2.0, but has been tested on 5.1.3 Beta2 - so can be applied if needed.

Attaching patch developed by Alex and tested by myself on 1 Master and 3 Slave servers. Additional tests highly recommended and appreciated. 


Related Tasks

INP-457 - Getting issue details... STATUS


  1. I suspected, that this task wasn't having it's own discussion in groups. Now
    it has one.
    On Sep 12, 2011 5:00 AM, "Dmitry A." <> wrote:

  2. You also haven't attached latest patch version with all the bug fixes we've
    found during testing in 1 master and 3 slave server configuration.

    I still need to create that patch from master server.
    On Sep 13, 2011 9:49 AM, "Alexander Obuhovich" <> wrote:

  3. Yes, please create a patch for this.

    Here is a reference to In-B task - #33346 - Setup MySQL Replication for