what storage should I use for user uploads and generated files

For user uploads and generated files, the best choice is usually object storage, not local disk or a database.

Recommended storage

Use a service like:

• Amazon S3
• Google Cloud Storage
• Azure Blob Storage
• Cloudflare R2
• MinIO if you need self-hosted/S3-compatible storage

Why object storage is best

It’s usually the right fit because it gives you:

• Scalability — handles lots of files easily
• Durability — designed to avoid data loss
• Low cost — especially for large or infrequently accessed files
• Easy CDN integration — good for serving downloads/images/videos
• Simple separation — app servers stay stateless

What not to use

• Local filesystem on app servers: okay only for temporary files or small single-server apps; breaks in autoscaling/multiple instances
• Database blobs: usually not ideal for large files; increases DB size and backup cost

Common pattern

Store files in object storage and keep only metadata in your database:

• file ID
• owner/user ID
• original filename
• storage key/path
• MIME type
• size
• checksum
• created_at
• status (uploaded, processing, ready, failed)

Good setup for uploads

1. User uploads file
2. App validates it
3. File is stored in object storage
4. App saves metadata in DB
5. Generated files are also written to object storage
6. Serve via signed URLs or CDN

Security tips

• Use private buckets by default
• Serve downloads with signed URLs or backend authorization
• Validate file type and size
• Consider virus scanning for untrusted uploads
• Use lifecycle rules to delete temp/generated files if needed

Practical recommendation

If you’re building a modern web app:

• Uploads and generated files: object storage
• Metadata/status: relational database
• Temporary processing files: local ephemeral disk or /tmp

If you want, I can recommend the best option based on your stack, e.g. AWS, Firebase, Vercel, Python/Django, Node/Express, or Rails.