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Moving app resources to the cloud means replacing or rehosting local servers, storage and databases with managed cloud services (compute, storage, DBs) so you get scalability, resilience and less ops work.

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Key managed database services

• Relational (managed): AWS RDS (MySQL/Postgres/SQL Server/Oracle), Azure Database, Cloud SQL (GCP).

• NoSQL / Document DB: AWS DocumentDB (and DynamoDB), Azure Cosmos DB, Firestore (GCP).

  Use managed DBs to avoid operating the database OS, backups and replication yourself.

Three common cloud storage types

1. Object Storage - great for unstructured files

• What: Put files (images, backups, logs, media) into buckets; each object gets a unique ID.
• Properties: Highly durable, distributed, auto-scales, accessible via HTTP APIs. Not a POSIX filesystem.
• Cloud names: AWS S3, Azure Blob Storage, Google Cloud Storage.
• Use cases: Backups, media, static website assets, data lakes.

2. Block Storage - VM disks

• What: A virtual raw disk you attach to a VM; you format and mount it like a hard drive.
• Properties: Fixed size, low-level block device, used for OS disks and databases on a VM. Usually single-instance attachment (can be multi-attach in some offerings).
• Cloud names: AWS EBS, Azure Managed Disks, GCP Persistent Disk.
• Use cases: VM root volumes, DBs on VMs, applications needing block-level access.

3. File Storage - shared filesystem