Multi master replication

• Multiple computers are allowed to execute write queries
  • This ensures that write-requests do not become the bottleneck of the system.
• This works in contrast with Chapter 1#Master-Slave Replication where only one master server is allowed to write while others are read only.
• Conflict handling methods are used for conflict resolution
• Communication and replication often implemented using a type of [[consensus-algorithm]].

Advantages

• High Availability
• Distributed Access
  • Masters can be located across multiple physical sites, giving distributed network access.

Disadvantages

• Most multi-master replication system are loosely consistent. Lazy and asynchronous. These violate ACID properties.
• Conflict resolution can get out of hands as the number of nodes increases.