MySQL cluster replication: Slave cluster should not store any data except data replicated from master cluster? I am researching MySQL cluster replication. I read a section "We assume that the slave server or cluster is dedicated to replication of the master, and that no other data is being stored on it" in MySQL cluster manual. According to the section, slave cluster should not store any data except data replicated from master cluster. 

I want to know for sure because I have an intention to deploy two cluster that a SQL node are both master and slave. 
Example: I have two clusters with SQL node A belongs to cluster a and SQL node B belongs to cluster b

SQL node A --- master of node B and also slave of node B  ---> SQL node B

SQL node B &lt;--- master of node A and also slave of node B ---> SQL node A

I think an bidirectional replication channel help me have two cluster for backup and scale out read/write (It allow web application to be read/write to two SQL nodes)

I am wondering the model is feasible ?
I do not see any problem (if you configure it properly: bin_log on, log_slave_updates, row replication, different server ids for all servers, same exact versions on all servers), but only if you use one of the clusters as read-only at any time.