Typically, the timeout is only reached if the selected new master server cannot consume its relay log quickly enough. When enabled, two types of servers are set to replicate from the current cluster master:. The monitor will look at the master binlog file positions of the slave servers and if they have advanced within a configured timeout, failover is not activated even if the monitor cannot connect to the master.
This means that at least one slave still receives events even if MaxScale cannot connect to the master. If the current master is showing any issues, you may want to promote a slave to take its place. The switchover-command takes three arguments: the monitor name, the slave to be promoted and the current master. This often causes replication to break as different servers have different events. Failover is activated when the master crashes or becomes unavailable.
MariaDB Monitor will detect that the master is out of reach, will wait for a while in case the master quickly comes back wait time is configurable , and finally begins failover to replace the failed master with a slave. Below is an excerpt of the MaxScale log. The typical use case for this feature is rejoining the old master after a failover.
Should the master come back online after a slave was already promoted to its place, it would not be immediately replicating. Auto-rejoin will detect this and redirect the master. This is not certain to succeed as the master may have conflicting events. In this case the slave thread will end in an error. In this case the monitor user should have, in addition to its normal rights, the ability to connect among the backends as well.
Knowledge Base Contact Login. Don't touch unless you know what you're doing! When enabled, two types of servers are set to replicate from the current cluster master: Standalone servers no slave thread Any server replicating from or attempting to from a server which is not the cluster master server.
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The primary node of a replica set instance is not fixed. When the configuration of the replica set instance changes, or the primary node breaks down, or a switchover is performed, the replica set will elect a node as primary, and the original primary node is demoted to the secondary.
Impact of a Switchover When the primary node becomes faulty, the system selects the secondary node as the new primary within 30 seconds. Service Deployment Suggestion Ensure that your application supports automatic reconnection. It is recommended that you use URLs to connect the cluster and replica set instances.
If an instance is under heavy load, you can change the instance class. Take a cluster instance as an example. For details, see Changing a Cluster Instance Class.
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