Windows Azure - Azure Storage and SQL Azure


In this article we are going to see what is an Azure Storage and different types of storage options available with Azure. Azure has two options for storage; one is Azure Storage and the other one is SQL Storage. This article is about the options available for the Azure Storage section. In the later section we will see a small outline of SQL Azure as well to get a clear idea of the differences.


Azure Storage has a very good advantage over SQL Azure; first of all it's inexpensive and can be used on a vast area when compared to the SQL Azure. Azure Storage is charged at 15 cents per gigabyte spent on the server compared to SQL Azure which is charged at 10$ per month for each gigabyte in the server. Azure Storage can be expanded as and when the process requires it to be and it's scalable and has many advantages compared to SQL Azure.

SQL Azure is nothing but the SQL version running in a cloud environment; we can't simply justify the statement since some of the features that SQL Server 2008 normally has are not available with the SQL Azure. Microsoft has provided a list of limitations and that can be viewed at:

Windows Azure Types:

Windows Azure has 4 types of Azure Storage sections as shown below:

1. Table Storage

2. Blob Storage

3. Queue Storage

4. Azure drives

Let us see the purposes and uses of each storage.

Table Storage:

This storage is used to store structured data, which are similar to a table but that are not relational. Table storages are prefered for storing Business entities in a structured format and it has significant advantages compared to the other ones. They are composed of a collection of properties, entities and properties further classified with a collection of names, types etc. The only disadvantage we can see with the table storage is that as and like a data access procedure we can't use ADO.Net to connect to the database, instead we need to use REST ful access using

Blob Storage:

Blob (Binary large Objects) as most of the developers should be familiar with is used to store images, documents or videos which are larger than something normally we store in a database like a sting or an id. Basically blob storage is used to storage binary data which are not easily compatible for storing larger data. This blog storage stores the data in containers which are either one of the two types:

  • Block blob
  • Page blob

Block blobs are limited to 200GB while page blobs are limited to 1TB which are very much used to store large data as and when required. As with table storage it has the same disadvantage of not being accessible using the normal ADO.Net; instead we can use the REST ful access using

Queue Storage:

Queue storages are used to do a message transport between applications as normally we would use MSMQ except in a cloud. This storage can be used to do transactions real time in sending and receiving messages. Queue messages are used to send messages of 8kb each and are not suitable for sending large objects as messages. So for doing transactions for the large objects in real time we can use an URI of the blob as a message for the transaction.

The messages will remain in the queue until deleted. If messages are read by one application then that message will be marked as invisible to the other application and will not be available online. Because of this we will not be sure of the order the process will happen for the message queues.

Azure Drives:

This storage drives allow access using the standard NTFS like we normally have it locally. The application which has the storage locally can be used to update the status locally and if we want to migrate this type of application to the cloud then Azure drives are used.


In this article we have seen the different storage options available with Windows Azure. In upcoming articles we will see how to implement each and every storage and the advantages of using them.

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