With its fully integrated solution for MySQL / MariaDB / Percona Server, Tungsten Clustering allows fine control of slave replicas:
- Want to keep a slave read-only? Have a node that will never be switched-to and become a master itself? Still want to allow client applications to read data from it? We call it "Archive Slave". It is particularly suitable for hosts that have low computational power and wouldn't hold the write workload. All you need is to type a single cctrl command:
/alpha > datasource host3 set archive
Managers will never turn an archive slave into a master, whereas connector will still route to it for read-only traffic.
- Prefer a slave as much up-to-date as possible? Protected from reads and that will preferably be selected in case of switch or failover? That's the stand-by node. By preventing read traffic, you dedicate computing and networking power to replication, keeping latency as low as possible. Similar simple command to make that happen:
/alpha > datasource host3 set standby
The connectors will exclude a standby node from their lists of slaves to send traffic to, so it can remain the most up-to-date slave and more likely to be selected for failover and switch.
Learn more about data source roles at http://docs.continuent.com/tungsten-clustering-6.0/operations-status-roles.html
For full documentation for setting and clearing standby and archive flags, visit http://docs.continuent.com/tungsten-clustering-6.0/operations-status-changingstates.html#operations-status-changingstates-standby