In this article I would like to summarize
the storage methods we learnt in Windows Azure.
The advanced features are also discussed here.
Types
of Storage
Recollecting that we have 3 types of
storage in Windows Azure:
- Local Storage
- Windows Azure Storage
- SQL Azure Storage
Below are some of
the advanced storage features.
Local Storage Features
This is a
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 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 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 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 of
installation and applying patches as these activities will be taken care 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
The 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 is:
- 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 good for small Web applications. The business edition can support up to 50 GB
of data and good for independent software vendors and enterprise applications.
The layers in SQL
Azure would be the following.
- Client Layer
- Services Layer
- Platform Layer
- Infrastructure Layer
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.