Database Reference
In-Depth Information
at any time. Additional database capacity can be added as desired until the subscription limit is
reached. he data may be distributed to multiple servers on Windows Azure for better scalability
and performance.
In this chapter, more details about Windows Azure are given. First, the infrastructure of
Windows Azure is briely described to obtain the whole picture. Previously, the Windows Azure
Management Portal has been used to develop databases on Windows Azure. However, we did not
go over the rest of the components provided by the portal. his chapter provides more informa-
tion about Windows Azure and the Windows Azure SDK. It also reviews the process of creating
a cloud-based application. he emphasis is on deploying the applications to a cloud environment.
It provides two hands-on activities. he irst one is to deploy the web form created in the previous
chapter. he second one is to develop a cloud-based reporting service.
10.2 Windows Azure
In this section, we will irst take a look at how Windows Azure is structured. hen, we will exam-
ine the features provided by Windows Azure.
10.2.1 Windows Azure Structure
Windows Azure is built on a set of nodes, each of which includes data storage devices and num-
bers of computers installed in a blade enclosure. he computers installed in the blade enclosure at
each node carry the computation workload. hese nodes are interconnected with high-speed wires
and switches called fabric and are controlled by a unit called Fabric Controller (FC). During the
development of applications, an FC unit monitors, provisions, and manages servers and resources
for the nodes in Windows Azure. he FC unit takes work orders from Windows Azure custom-
ers and selects the nodes to handle the work orders. After the work is completed, the FC returns
the results back to the Windows Azure customers. he FC works with another unit called Load
Balancer to make sure that none of the nodes is overworked. hrough routers, the Windows Azure
customers are able to interact with the Load Balancer and FC. he Windows Azure architecture
is illustrated in Figure 10.1.
he FC, Load Balancer, and Nodes together are also called Azure Fabric. Various cloud ser-
vices have been developed on top of Azure Fabric.
Windows Azure stores its data in data centers across the world. Windows Azure customers are
able to remotely access these data centers. If the data are stored in multiple data centers, applica-
tion developers can use Windows Azure Traic Manager to manage the network traic among
data centers. Windows Azure also allows customers to access the data stored on an on-premises
server through an application on Windows Azure.
he free Windows Azure SDK package is available for developing and testing the applications
on local computers. It includes the compute emulator and storage emulator to provide a develop-
ment environment that is similar to the one on Windows Azure. On a local computer, the com-
pute service and storage service can be created with the compute emulator and storage emulator.
he Windows Azure SDK also includes tools for testing the applications created on local comput-
ers and deploying the applications to Windows Azure.
An application can be deployed at the staging level or production level. At the staging level, an
application developer can develop an application and test it in Windows Azure. When the appli-
cation is ready, it can be published as a cloud service to the public. At that point, the application
