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Hi! I'm interested in scaling MariaDb with active-active replicas. They call it ring replication: https://mariadb.com/kb/en/replication-overview/ https://mariad

by hu3 5y ago

Hi! I'm interested in scaling MariaDb with active-active replicas. They call it ring replication: https://mariadb.com/kb/en/replication-overview/ https://mariadb.com/kb/en/replication-overview/ I would appreciate any comments. Specially on the upsides and downsides.

ericyan 5y ago
That's a footgun. For ring replication to work, it requires all replication sources (aka. "masters") to be online at all times. This never happens in real life, so it is just a matter of time that you get a nasty split-brain. Star replication tries to mitigate this by a crazy setup with replication filters that is painful to maintain and probably will break after some DDL statements. Moreover, neither of these can handle conflicts. If a row gets updated on different hosts at the same time, you will get broken replication and/or split-brain. To scale writes, sharding is usually the way to go and Vitess can be handy for that. By the way, MySQL group replication has multi-primary mode that is safer. Galera Cluster/PXC probably has something similar but I am not completely sure.
- samlambert 5y ago
  This.
- hu3 5y ago
  Thank you! I'll be looking into Galera then.