We are setting up a georedundant database system that currently has two clusters nodes with XDCR configured. Next we would like to add two more cluster nodes to this setup but this is where it all gets a bit tricky.
Although I have read the Couchbase documentation several times I still haven’t found the answer to my question - What is the maximum count of cluster nodes one can have in XDCR setup? Please do note that I’m talking about multi master database system.
In the documentation and in the web I only see three cluster node XDCR setups. Can I have more clusters than that and what is the absolute maximum limit?
I would also be interested to know (if Couchbase supports more that 3 cluster nodes in the XDCR) how the Couchbase handles the data consistency in multi master setups. A link to some onlide document would be appreciated…
rule of thumb is for each XDCR stream you have. Give it a dedicated CPU core. So more cores you have the better.
"how the Couchbase handles the data consistency in multi master setups."
This is tricky. You are going to have to test to see how the chain SET()s of data goes from cluster to cluster. In XDCR from two data centers I normally have data center one generate odd key EX “xyz_1 , xyz_3 …” and the other “xyz_2 , xyz_4”… so I can see how the bounce back in forth. Another thing you want to do is in you json make sure you id where the JSON was made and/or updated at.