Implementing binlog streaming in SQL Galera Cluster for backup and replication purposes

26 Sep 2023

Introduction

In a SQL Galera Cluster, implementing binlog streaming is essential for backup and replication purposes. Binlog streaming allows you to capture changes made to the database at the transactional level, enabling you to replicate these changes to other nodes in the cluster or create backups for disaster recovery. In this blog post, we will explore how to implement binlog streaming in SQL Galera Cluster.

Prerequisites

Before we proceed, make sure you have the following prerequisites in place:

SQL Galera Cluster installed and running on your server.
Read/Write access to the my.cnf configuration file on all the nodes in the cluster.
Basic knowledge of MySQL replication and Galera Cluster architecture.

Steps to Implement Binlog Streaming

Follow the steps below to implement binlog streaming in SQL Galera Cluster:

Edit the my.cnf file on each node in the cluster and enable binary logging by adding or modifying the following line:
```
log_bin = /var/log/mysql/mysql-bin.log
```
Make sure to provide the correct path for the binary log file.

#GaleraCluster #BinlogStreaming
Restart MySQL on each node to apply the changes.
```
sudo systemctl restart mysql
```
Verify the binary logging is enabled by connecting to any node in the cluster and executing the following command:
```
SHOW VARIABLES LIKE 'log_bin';
```
You should see the log_bin variable set to the specified file path.
Configure replication on the nodes you want to replicate data to. Connect to the respective node and execute the following commands:
```
STOP SLAVE;
CHANGE MASTER TO MASTER_HOST='<source_node_ip>', MASTER_USER='<replication_user>', MASTER_PASSWORD='<password>', MASTER_LOG_FILE='<log_file>', MASTER_LOG_POS=<log_position>;
START SLAVE;
```
Replace the placeholders with appropriate values:
- <source_node_ip>: IP address or hostname of the node you want to replicate from.
- <replication_user>: MySQL user with replication privileges.
- <password>: Password for the replication user.
- <log_file>: The log file name from the source node.
- <log_position>: The log position from the source node.
Verify the replication status by executing the following command on the node you configured for replication:
```
SHOW SLAVE STATUS\G
```
Look for the Slave_IO_Running and Slave_SQL_Running fields to ensure both are set to Yes.

Conclusion

Implementing binlog streaming in SQL Galera Cluster allows you to replicate changes made to the database across nodes and create backups for disaster recovery. By following the steps outlined in this blog post, you can enable binlog streaming and configure replication in your Galera Cluster setup.

With binlog streaming, you gain the ability to have a highly available and scalable database cluster with reliable replication mechanisms in place.

Give it a try and let us know how it worked for you!

#GaleraCluster #BinlogStreaming