Yes, our MongoDB replica cluster writes a lot of data.
The write level of the program is: {w: “majority”}
Initially, this MongoDB replica cluster had three nodes, but two of them went down, and I removed the two down nodes from the cluster.
Then I newly deployed a node of the same version, added it to the original replica set, and synchronized data through the internal synchronization mechanism of the MongoDB replica set. When the node role is normal and the optime is consistent through rs.status(), I observe the newly synchronized node There are missing data in the collection.
I later deployed another node to join the cluster. After the latest node synchronization is completed, this node has the same data as the master node. So far, among the three nodes, the node data for the first synchronization is still missing collection records.
So it is very strange why this phenomenon occurs.