does my meteor app needs both MONGO_OPLOG_URL and MONGO_URL

Question

I'm deploying my Meteor app on Modulus.io and for my database using compose.io with oplog, I'm setting up environment url's I wondering if I need both MONGO_OPLOG_URL and MONGO_URL or just the MONGO_OPLOG_URL

Answer 1

MONGO_URL is the URL your app uses to communicate with your mongo instance. It is required for all production applications. Oplog transactions are not communicated through this URL.

MONGO_OPLOG_URL is the URL your app uses to listen for changes to the binary oplog for your database. It is not required, but highly recommended.

Summary: add both.

For more information see this article.