Getting started with Azure storage: Blobs vs Tables vs SQL Azure

Question

It's quite a topic, blobs vs tables vs SQL, and despite all, I read so far I still can't find some proper reasoning on what to use when.

We have a multi-tenant SaaS web-application which we are about to move to Azure. We use an SQL Server 2008 database. We store documents and log information that belongs to the documents. Kinda like Dropbox does.

The forums state that you better use Azure Tables when you are considering "large" objects. Do we typically store hundreds of documents per user where the size of the documents varies from 5kb to 30mb where the vast majority will be around 1MB?

Are there some ground rules when to go for Blobs, Tables, SQL? I already learned that I shouldn't store my documents in SQL since it is too expensive. But when does it get "beneficial" to store the documents in Blobs and when would I be better off with tables? Is there some kind of formula like :

if (objects * MB/object * objectrequested > y) then blobs, else tables

Answer 1

Well if you are confused between Azure Blob and Table, here is a blog that will help, click here.

You can use Tables when your data is flexible and has a lot of metadata. Whereas, blobs are suggested when you just want to stream your data or access from anywhere and also the data does not contain a lot of metadata. 

The options can be quite overwhelming and confusing but it is better to know what type of data you have and how comfortable you are with tables, blob or SQL. 

Deciding whether to use Azure SQL database or Azure storage in itself can be quite complex. 

Here is a blog that talks about how to choose the right data store. Click here for more insights.