Which Database Works Best for Multi-Master Replication?

Multi-master replication allows database nodes to accept write operations, improving availability and fault tolerance. However, the choice of database for such a setup often depends on specific use cases, scalability needs, and consistency requirements. This article explores various databases known for their multi-master replication capabilities and the factors to consider when selecting the best fit for your application.

IBM's Informix - Enterprise Replication (ER)

IBM's Informix supports full multi-master replication through its Enterprise Replication (ER) feature. This feature includes multiple methods for conflict resolution when the same row is updated from multiple cluster nodes nearly simultaneously. ER also synchronizes all nodes in the cluster in case of data divergence. The configuration is straightforward and can be applied to single tables or entire databases, with options to limit replication to only parts of the rows or all rows.

Topologies supported by Informix ER:

P2P (Peer-to-Peer) Master-Slave Scatter (Nodes hold relevant subsets of data or a full set) Gather (Local updates forwarded to the central repository)

Multi-Master Replication Capabilities in Major Databases

Cassandra

Cassandra is a NoSQL database known for its high scalability and high availability. It uses a peer-to-peer architecture, allowing any node to accept writes. This makes it a good choice for distributed and scalable applications.

DynamoDB

DynamoDB is a managed NoSQL database service that offers automatic multi-region replication. It is designed for high availability and low latency, making it suitable for applications that require highly available and low-latency access to data.

MySQL with Group Replication

MySQL with Group Replication supports multi-master replication through group replication. This solution allows for conflict detection and resolution, making it a viable option for applications that require high availability and fault tolerance.

PostgreSQL with BDR (Bi-Directional Replication)

PostgreSQL with BDR (Bi-Directional Replication) enables multi-master replication. Changes can be made on any node, making it a good fit for applications that require dynamic and distributed data access.

MongoDB with Sharded Clusters

MongoDB with Sharded Clusters supports replica sets and allows for some multi-master configurations. While traditional replica sets are single-master, sharded clusters offer more flexibility, making them suitable for certain distributed environments.

CockroachDB

CockroachDB is designed for cloud-native applications and supports multi-region deployments. It offers strong consistency with high availability, making it a robust choice for multi-master replication scenarios.

Galera Cluster

Galera Cluster is a MySQL/MariaDB plugin that provides synchronous multi-master replication. This plugin enables true multi-master capabilities, making it a strong contender for applications requiring high availability and fault tolerance.

Factors to Consider When Choosing a Database for Multi-Master Replication

When selecting a database for multi-master replication, consider the following key factors:

Conflict Resolution: How the database handles conflicts that arise from concurrent writes, such as data inconsistencies or race conditions. Latency: The impact of replication lag on data consistency. Low latency is crucial for applications where timely access to data is essential. Scalability: The ability to add nodes without significant performance degradation. A scalable solution can manage increasing loads without compromising performance. Consistency Model: Whether the database supports strong or eventual consistency. Understanding the consistency model in relation to your application requirements is vital.

The best choice ultimately depends on your specific application requirements and architecture. Carefully evaluate these factors to ensure that the database you choose meets all your needs for availability, fault tolerance, and performance.