diff options
Diffstat (limited to 'health/guides/mysql/mysql_galera_cluster_size_max_2m.md')
| -rw-r--r-- | health/guides/mysql/mysql_galera_cluster_size_max_2m.md | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/health/guides/mysql/mysql_galera_cluster_size_max_2m.md b/health/guides/mysql/mysql_galera_cluster_size_max_2m.md new file mode 100644 index 00000000..0f14ca8a --- /dev/null +++ b/health/guides/mysql/mysql_galera_cluster_size_max_2m.md @@ -0,0 +1,40 @@ +### Understand the alert + +This alert calculates the maximum size of the MySQL Galera cluster over a 2-minute period, starting from one minute ago. If you receive this alert, it means that there has been a significant change in the cluster size, which might affect the database's performance, stability, and data consistency. + +### What is MySQL Galera Cluster? + +MySQL Galera Cluster is a synchronous multi-master cluster for MySQL, built on the Galera replication plugin. It provides high-availability and improved performance for MySQL databases by synchronizing data across multiple nodes. + +### What does the cluster size mean? + +The cluster size refers to the number of nodes participating in a MySQL Galera Cluster. An optimal cluster size ensures that the database can handle more significant workloads, handle node failures, and perform automatic failovers. + +### Troubleshoot the alert + +- Determine the current cluster size + + 1. Connect to any node in the cluster and run the following SQL query: + + ``` + SHOW STATUS LIKE 'wsrep_cluster_size'; + ``` + + 2. The query will display the current number of nodes in the cluster. + +- Identify the cause of the cluster size change + + 1. Check the MySQL and Galera logs on all nodes to identify any issues, such as network connectivity issues, node crashes, or hardware problems. + + 2. Review the logs for events such as joining or leaving of the cluster nodes. Look for patterns that could lead to instability (e.g., frequent node join & leave events). + +- Resolve the issue + + 1. Fix any identified problems causing the cluster size change. This may involve monitoring and resolving any network issues, restarting failed nodes, or replacing faulty hardware. + + 2. If necessary, plan and execute a controlled reconfiguration of the Galera cluster to maintain the optimal cluster size. + +### Useful resources + +1. [Galera Cluster Documentation](https://galeracluster.com/library/documentation/) +2. [Monitoring Galera Cluster for MySQL or MariaDB](https://severalnines.com/database-blog/monitoring-galera-cluster-mysql-or-mariadb)
\ No newline at end of file |