With this configuration, in which the different neo4j DBMS are in different locations, if the connection between them and the Causal Cluster is cut for several hours, would the user be able to make queries about these dbms?
Does the Cluster work fine if it was connected to 20K neo4j dbms in different locations?
Would it be a valid system for a production environment?
Thanks in advance...
You have to have network connectivity. A multi-dbms query with fabric will not be successful if a network partition has taken one of the DBMSs entirely offline. It's just a neo4j bolt connection between DBMSs and the transaction in this situation cannot be satisfied.
On the other hand, if fabric is talking to multiple databases in one DBMS that is geographically distributed, this may be over-comeable. To confirm transactions a majority of a DBMS is necessary, but not unanimity. So for example of 2 of 3 cluster members are network available, it will still work.
If an entire cluster becomes network unavailable, or a majority of any participating DBMS becomes unavailable, then it won't.