Galera Cluster vs MaxScale: What are the differences?

Introduction

In this Markdown code, I will provide the key differences between Galera Cluster and MaxScale, two popular technologies used for database clustering and management.

1. Synchronous vs Asynchronous Replication: One significant difference between Galera Cluster and MaxScale is their approach to replication. Galera Cluster is based on synchronous replication, which means that every write operation is committed on all nodes before it is considered successful. On the other hand, MaxScale uses asynchronous replication, where write operations are first committed on the primary node and then asynchronously replicated to secondary nodes. This difference impacts the consistency and latency of data replication between nodes.

2. Architecture: Galera Cluster has a peer-to-peer architecture where all nodes are equal and can accept both read and write operations. Each node regularly communicates with each other to maintain consistency. In contrast, MaxScale has a master-slave architecture, where there is one primary node that handles write operations, and several secondary nodes that handle read operations. This architectural difference affects the scalability and performance characteristics of the system.

3. Granularity of Load Balancing: Galera Cluster provides load balancing at the transaction level, meaning that each transaction can be routed to a different node in the cluster. This provides better load distribution and helps in scaling the read and write workload. On the other hand, MaxScale provides load balancing at the session level, where a session is assigned to a specific node and all subsequent requests from that session are routed to the same node. This can result in uneven load distribution if some sessions are more resource-intensive than others.

4. Supported Databases: Galera Cluster is designed to work with MySQL and MariaDB databases and provides synchronous multi-master replication specifically for these databases. MaxScale, on the other hand, is a database proxy that supports multiple databases, including MySQL, MariaDB, and PostgreSQL. It provides various advanced features for database management and query routing.

5. Integration with Other Technologies: Galera Cluster integrates tightly with the underlying database software and requires modifications to the MySQL or MariaDB server binaries to enable the Galera Replication Plugin. MaxScale, being a separate software layer, can be easily deployed alongside the database server and does not require modifications to the database binaries. This makes MaxScale more flexible in terms of deployment and easier to integrate into existing infrastructures.

6. Management and Monitoring Features: Galera Cluster provides a comprehensive set of management and monitoring tools, such as Galera Observer and Galera Manager, to manage and monitor the cluster. These tools offer features like cluster-wide monitoring, monitoring of replication consistency, and handling node failures. MaxScale, on the other hand, offers a web-based administration console called MaxAdmin, which provides centralized management and monitoring capabilities for multiple servers and clusters.

In summary, the key differences between Galera Cluster and MaxScale include the replication approach (synchronous vs asynchronous), architecture (peer-to-peer vs master-slave), granularity of load balancing (transaction level vs session level), supported databases, integration with other technologies, and management/monitoring features.