Why Is the Delay High In MongoDB Replication Scenarios?

Involved Scenarios

• Migration from MongoDB to DDS
• Migration from DDS to MongoDB
• Synchronization from DDS to MongoDB

Possible Causes

To ensure the performance of migration, synchronization, or disaster recovery, DRS performs concurrent replay at the collection level in the incremental phase. In the following special cases, DRS supports only single-thread write and does not support concurrent replay:

• The collection index contains a unique key.
• The value of capped of the collection attribute is true.

If the delay increases, check whether the problem is caused by the preceding reasons.