If you’re upgrading a ReplicaSet from a version before 3.2 of MongoDB to a new version, you will run into this warning when connecting to the shell. Protocol Version 0 is not supported in MongoDB 4.0. Checking Protocol Compatibility To verify which protocol version...
MongoDB Blog Posts
MongoDB – WARNING: readConcern:majority is enabled
If you're running a 3 member ReplicaSet that uses an Arbiter as its third member, then you will be presented with this warning when you connect to the shell. When a node goes down in a PSA architecture (Primary, Secondary, Arbiter) the wiredTiger storage engine starts...
MongoDB – WARNING: This server is using MONGODB-CR
MongoDB-CR is the challenge response authentication mechanism used in MongoDB versions before 4.0. In version 4.0 this mechanism is removed and you must upgrade to the new mechanism SCRAM before you upgrade to 4.0. You will receive this warning if you have launched...
MongoDB – WARNING: This Server is bound to localhost
When you're upgrading from previous versions before 3.6 you might notice this warning showing up in the shell when you start the server for the first time. This warning is telling you that you don't have an IP bound to your instance, preventing any connections to the...
MongoDB – Disabling Transparent Huge Pages Ubuntu 16.04+
When running a MongoDB instance, it's always important and even recommended to disable Transparent Huge Pages. Database workload can be poor when THP is enabled. Service File This service will allow you to disable THP during startup. Create the service file we'll use....
The Pros and Cons of MongoDB
MongoDB is one of the world's most popular object-oriented NoSQL databases. But like any other database, MongoDB has specific places where it flourishes and areas where it falters. The Question: To Use Or Not To Use Some of the best ways to utilize MongoDB is when...
MongoDB: Mtools and Slow Queries
Mtools is a third party tool suite that contains very easy to use utilities for troubleshooting or just gathering general knowledge about your MongoDB instance. These tools can be crucial when performance tuning, running a health check or examining log files. You can...
MongoDB Sudden Slow Database Performance
Sometimes you may notice that everything in MongoDB is running fine, then you suddenly have performance issues that come up out of nowhere. There can be several reasons why this happens but I am going to cover a few of the common ones here. Long-running queries Index...
Troubleshooting Slow Queries in MongoDB
There are many reasons why your database queries can start to lag or experience throughput issues. In this article I will do troubleshooting on two common issues with slow queries and a way to fix each one. When doing any performance tuning on a database it's...
MongoDB ServerStatus Health Check Tips
MongoDB ServerStatus is the main command used to produce a huge document containing important metrics and information about your database. When performing a health check, there are several important keys that you'll want to be aware of inside serverStatus. The output...