Hi @Mat_Jung,
MongoDB Atlas is a managed database service – you don’t have to worry about the underlying administrative knowledge and tasks to configure, secure, monitor, backup, and scale your MongoDB deployments.
I recommend starting with the MongoDB Atlas product page and MongoDB Atlas FAQ, but will try to address the specific questions you’ve asked here.
What is an Atlas cluster?
An Atlas cluster is a MongoDB deployment (currently a replica set or sharded cluster) managed by the MongoDB Atlas service. Atlas clusters may either have shared resources (for example, M0 free tier clusters and M2/M5 clusters) or dedicated resources (M10+). The M# reference refers to a specific Atlas cluster configuration, with larger numbers generally indicating clusters with more resources.
Atlas creates and manages clusters on supported cloud providers (currently AWS, GCP, and Azure) and provides a single bill for your database management and hosting. Atlas also integrates a growing set of cloud features including Atlas Search (full text search with Lucene), Atlas Data Lake (query and analyse data across AWS S3 and Atlas), and MongoDB Realm (serverless apps and mobile sync).
The minimum Atlas cluster deployment is a 3 member replica set running MongoDB Enterprise configured with best practice features such as role-based access control, TLS/SSL network encryption, firewall restrictions, and monitoring. You can configure additional features and behaviour via the Atlas UI or API.
Your team is still generally responsible for capacity planning and choosing when to scale clusters up (or down), but with dedicated clusters you can also choose to configure Cluster Auto-Scaling to adjust cluster tier or storage based on thresholds.
What is a cloud provider?
Supported cloud providers (currently Atlas, GCP, and Azure) provide the hosting infrastructure (virtual machine instances, storage, …) where the Atlas service will create and manage your clusters. You can choose your preferred cloud provider and region(s) to match other other aspects of your use case (for example, choosing a provider and region to reduce network latency between your application servers and your Atlas cluster).
What is the Atlas free tier?
The Atlas free tier gives you access to a shared deployment running on one of the supported cloud providers. Free tier clusters are intended to be used as development sandboxes: they have a storage limit of 512MB of data and some operational limitations including throughput, connections, and data transfer limits.
Are there advantages to using Atlas versus self-hosting with the same cloud providers?
You can create a self-hosted MongoDB deployment, but are then responsible for all of the administrative tasks and infrastructure setup/maintenance (security, monitoring, backup, scaling, upgrades, etc). Atlas automates common administrative and operational challenges so your team can focus on development.
MongoDB = database server software
Cluster = a MongoDB deployment (Atlas clusters are replica sets or sharded clusters)
Atlas = cloud-hosted interface to manage your clusters (deployment, security, monitoring, and backup)
Cloud Provider = the cloud hosting provider where your managed instances are created by Atlas (currently AWS, GCP, or Azure)
Free Tier Cluster = a free Atlas cluster you can use for development and testing
Regards,
Stennie