MySQL Cluster: Difference between revisions

Revision as of 12:50, 17 October 2024

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===Replication===

Internally MySQL Cluster uses [[synchronous replication]] through a [[two-phase commit]] mechanism in order to guarantee that data is written to multiple nodes upon committing the data. (This is in contrast to what is usually referred to as "MySQL Replication", which is {{linktext|asynchronous}}.) Two copies (known as ''replicas'') of the data are required to guarantee availability. MySQL Cluster automatically creates “node groups” from the number of replicas and data nodes specified by the user. Updates are synchronously replicated between members of the node group to protect against data loss and support fast failover between nodes. Cluster replication differs from "MySQL Replication", which is instead {{linktext|asynchronous}}.

It is also possible to replicate asynchronously between clusters; this is sometimes referred to as "MySQL Cluster Replication" or "geographical replication". This is typically used to replicate clusters between data centers for [[IT disaster recovery]] or to reduce the effects of network latency by locating data physically closer to a set of users. Unlike standard MySQL replication, MySQL Cluster's geographic replication uses [[optimistic concurrency control]] and the concept of Epochs to provide a mechanism for conflict detection and resolution,<ref>[http://dev.mysql.com/doc/refman/5.6/en/mysql-cluster-replication-conflict-resolution.html MySQL :: MySQL 5.6 Reference Manual :: 17.6.11 MySQL Cluster Replication Conflict Resolution]. Dev.mysql.com. Retrieved on 2013-09-18.</ref> enabling active/active clustering between data centers.