Issue

Running a small 3 replica set MongoDB instance (same server). All mongo processes terminated with the error:

,"s":"E",  "c":"ASSERT",   "id":23077,   "ctx":"ftdc","msg":"Assertion","attr":{"error":"BSONObjectTooLarge: BSONObj size: 47366592 (0x2D2C1C0) is invalid. Size must be between 0 and 16793600(16MB) First element: start: new Date(1749580651000)","file":"src/mongo/bson/bsonobj.cpp","line":129}}

There was very little usage at the time, no users on the system or load. It looks like the BSONObjectTooLarge error was generated by the FTDC service.   

Questions

• How do I diagnose why FTDC tried to create such a large BSON object?
• Are there any further files I can provide to help diagnose?
• This is a production system can I turn off FTDC until the underlying issue is fixed? Is it safe to disable?

Environment

MongoDB 8.0.9 (3 Replica set)

1 database (12GB)

Ubuntu 24.04.2 LTS

32GB RAM 8 core VPC

Other

May be a bug linked to this issue?

https://jira.mongodb.org/browse/SERVER-101459?jql=text%20~%20%22BSONObjectTooLarge%20FTDC%22

Also reports of this error on the MongoDB forum.

https://www.mongodb.com/community/forums/t/hi-all-my-mongodb-service-went-down-due-to-an-error-bsonobjecttoolarge-this-error-occurred-because-a-single-document-exceeded-the-16mb-size-limit/313820/3

https://www.mongodb.com/community/forums/t/random-crashes-due-to-ftdc-causing-bsonobjecttoolarge-error/313183