Have a 2 replicasets (with 5 nodes in each, but it doesn't matter), need to create a new one replicaset and move some dbs and collections, from those 2 replicaset, without downtime. My first thought was to add my new nodes to first replicaset and copy dbs by replication, after that create a replicaset with new nodes and delete unnecessary data from it. But this would work with replication from one replicaset, but what about the second.
Fount another solution https://stackoverflow.com/a/11554877, but in this case I will have a downtime, during the time of backuping and restoring, new data will appear and they will not reach the new database? Or im wrong and everything will be ok?
