Node.js – How to Specify Azure Storage Connection String

Windows Azure Storage (and I'm assuming you're referring to blobs) does not have a limit to the number of objects you can store. It's only limited by the 200TB-per-storage-account cap. And you can have multiple storage accounts in your subscription (each storage account maps to a namespace such as mystorage.blob.core.windows.net).

Same goes for Table storage: no limit to the number of tables or the number of entities per table. Just the 200TB restriction.

Now, as far as directories go: Blob storage is organized by namespace.blob.core.windows.net/containername/blobname.ext. These aren't really directories. If you want true filesystem directories, you'll need to set up a disk in a blob (basically a vhd formatted as ntfs / ext3 / ext4 etc) and mounted to your OS disk. A disk is limited to 1TB (the max. size of a page blob). Once you do that, you have a complete file system to write to. Just a warning though: Only one VM can attach to a drive at a given time, so this isn't ideal if you're trying to have a file-share set up (direct blob storage is much better for that, or you'll need to set up an smb server for yourself).

One more thing about Azure storage: You don't have to worry about sharding; this is a massive-scale durable data storage system. Each blob is in its own logical partition, and the storage service organizes / reorganizes storage as necessary. This is something you don't need to worry about. The only thing I guide against is storing all objects in a single container, since enumerating blobs within a container could take a while if you have 10's of thousands of objects there. I typically don't enumerate containers, since I usually store blob uri's in another database as metadata (maybe in a SQL store, or MongoDB document store).

Azure Web Apps (websites) provide an Application settings configuration area that you can access to store these types of settings:

These settings may be in your web.config, as you already discovered. However, if you specify them in your Application settings for your Web App, the web.config values will be overridden by values found in Application settings (see this article which mentions this specifically).