Restoring Mongo Data Using the Oplog

Everyone who works with data worries about accidental deletion and should have a good understanding of recovery strategies, ideally before an incident occurs. If you’re using Mongo, you can restore data to an arbitrary point in time using the oplog, provided you are using replication and have a recent backup.

This blog post will walk you through a simple data deletion and recovery scenario using this method, and should be accessible even if you have limited experience with Mongo.


Debugging with the MongoDB oplog

Debugging allows us developers to assume the role of detective, and like any good detective, we need to consult all of our sources to understand what’s going on. If your application uses MongoDB for persistence, one source you have available is the oplog. What is the oplog? The MongoDB oplog, or operations log, is a standard capped MongoDB collection. Each document in the collection is a record of a write operation (a delete, update or insertion) that has resulted in data being changed.