Types of Storage
Recalling that we have 3 types of storage in Windows Azure:
- Local Storage
- Windows Azure Storage
- SQL Azure Storage
![SQLAzure Storage]()
Below are some of the advanced storage features.
Local Storage Features
This is temporary storage and the application cannot see the underlying disk
or drive on which the storage is done. But the application can request up to 1
GB of data on the local storage.
The local storage space is not accessible outside or to any other instances.
Windows Azure on the runtime chooses the best drive to store the data.
Windows Storage Features
The Windows Azure operating system allows 4 kinds of storage which are Blob,
Table, Queue and Disk storage.
These storage accounts are publicly exposed so we can access they from virtually
anywhere. The storage account data is exposed using HPTTP, REST and OData
protocols.
The Blob storage provides a huge amount of data manipulation. The table storage
provides structured data processing as entities and Queue storage is efficient
in back end and front end communication.
In Windows Azure Storage, there is one more type called Drive storage. Windows
Azure Drive allows us to upload Virtual Hard Drives as Blob. This provides great
flexibility to developers. More information can be found here.
Automatic Replication is a feature that makes sure the data stored is replicated
3 times. This is taken care of by the Content Delivery Network (CDN) and improves
the performance.
Geo-replication is a new feature that provides replication for Blob and Table
data at no additional cost. This provides the reliability during a crisis
situation.
Queue Insert Message Timeout is a new feature that makes the queue message
invisible until the specified time expires.
Table Query Projection is a new feature that allows partial reading of entity's
properties. This will improve the performance.
REST and Managed APIs support working with storage services. We need to download
the REST API SDK to achieve this.
Pricing of Windows Azure Storage is performed based on the average usage of
blob, table, queue and drive storage.
The updated information can be found here.
SQL Azure Storage Features
SQL Azure represents the Cloud version of SQL Server. It is a highly available and
scalable database on the cloud premises.
SQL Azure provides ease of use and maintenance. No need to install and
apply patches as these activities will be taken care of by the provider.
ADO.NET, ODBC and JDBC providers are supported on SQL Azure.
The design time structure and data management can be done through:
- Windows Azure Portal
- SQL Azure Management Portal
- MMC Tool
- SQL Server Management Studio
SQL Azure provides automatic replication of data and automatic switching
of the server in case of failures.
Some of the current drawback of SQL Azure are:
- Not all data types in SQL Server are supported
- SSAS (SQL Server Analysis Services) not supported
- Service Broker feature not supported
The editions in SQL Azure are the following:
- Web Edition
- Business Edition
The web edition can support 1 GB or 5 GB in size and is good for small Web
applications. The business edition can support up to 50 GB of data and is good for
independent software vendors and enterprise applications.
The layers in SQL Azure are the following.
- Client Layer
- Services Layer
- Platform Layer
- Infrastructure Layer
![Storage in SQLAzure]()
The Client layer is hosted in Windows Azure and communicates with our
application. The Service layer acts as a gateway between the client layer and
the platform layer. The Platform layer includes the physical servers which
supports the service layer. The Infrastructure layer consists of the IT
administration of the physical hardware and operating systems that supports the
service layer. More information can be found here.
Summary
In this article we have summarized the types of storages in Windows Azure and
the advanced features provided by them.