How do I check my Galera cluster status?
I know to check the Galera cluster status, the command that should be used after login to the mysql client is: SHOW STATUS LIKE ‘wsrep%’;
What is a Galera cluster?
Galera is a multimaster MySQL cluster that provides virtually synchronous replication by certifying so called “write-sets”, which ensures that all database transactions are committed on all cluster nodes. The software is developed and maintained by Codership.
How do you get a Galera Cluster?
- Step 1 — Adding the MariaDB Repositories to All Servers.
- Step 2 — Installing MariaDB on All Servers.
- Step 3 — Configuring the First Node.
- Step 4 — Configuring the Remaining Nodes.
- Step 5 — Opening the Firewall on Every Server.
- Step 6 — Creating a SELinux Policy.
- Step 7 — Starting the Cluster.
- Step 8 — Testing Replication.
What do you need to know about Galera Cluster?
Monitoring a Galera Cluster ¶ Galera Cluster is a reliable, stable database replication clustering system. Both MySQL and MariaDB, with the InnoDB storage, utilize Galera for communications between nodes running Linux. Every aspect of such an arrangement is equally dependable for maintenance and availability of data.
When does wsrep notify CMD in Galera Cluster?
2015-04-29 11:49:38 49655 [Note] WSREP: Synchronized with group, ready for connections 2015-04-29 11:49:38 49655 [Note] WSREP: wsrep_notify_cmd is not defined, skipping notification. 2015-04-29 11:49:39 7ff1285b5700 InnoDB: Error: page 409 log sequence number 207988009678 InnoDB: is in the future! Current system log sequence number 207818416901.
Where do I find the error log in Galera?
The error log should provide details to help troubleshoot the problem. This is usually, /var/log/mysqld.log —or whatever the value is for log_error variable. To make the node status much clearer, you can check the value of the wsrep_local_state_comment status variable.
What are the status variables in MySQL Galera?
In addition to the standard status variables in MySQL you may already monitor, Galera Cluster also provides a set of status variables. They will allow you to check node and cluster states, as well as replication health. Galera Cluster variables are related to write-set replication and thereby prefixed with wsrep_.