When we insert 700 million data with MongoDB 3.4.10, it needs 4.5 hours. But when we upgrade to MongoDB 4.0.5, it needs 6.5 hours. As time goes on, insert the same data need more and more time. Where can I check the setting to improve my performance.

In MongoDB 3.4.10 cache dirty under 6%, but in MongoDB 4.0.5 cache dirty will up to 20%. We install MongoDB with default setting, and disable NUMA. Related content as attachments, thanks a lot!!