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How can I troubleshoot my MongoDB replica set?
Check the network routes between the members of your set to ensure that there is no packet loss or network routing issue. Use tools including ping to test latency between set members and traceroute to expose the routing of packets network endpoints.
Can a client connect to MongoDB 3.6 binaries?
When bound only to the localhost, these MongoDB 3.6 binaries can only accept connections from clients (including mongosh and other members of your deployment in replica sets and sharded clusters) that are running on the same machine. Remote clients cannot connect to the binaries bound only to localhost.
How does syncedto work in MongoDB for delayed members?
Returns the syncedTo value for each member, which shows the time when the last oplog entry was written to the secondary, as shown in the following example: A delayed member may show as 0 seconds behind the primary when the inactivity period on the primary is greater than the members [n].secondaryDelaySecs value.
Where are the slow OpLog entries in MongoDB?
These slow oplog messages are logged for the secondaries in the diagnostic log under the REPL component with the text applied op: took ms. These slow oplog entries depend only on the slow operation threshold.
What does replication lag in MongoDB mean?
Replication lag is a delay in data being copied to a secondary server after an update on the primary server. Short windows of replication lag are normal, and should be considered in systems that choose to read the eventually-consistent secondary data.
When to run replsetgetstatus on a member in MongoDB?
Starting in MongoDB 4.2.1, If you run replSetGetStatus on a member during its initial sync, the command returns replSetGetStatus.initialSyncStatus metrics. Once the member finishes its initial sync and transitions to another state,the replSetGetStatus.initialSyncStatus metrics is no longer available.