discover the three major components of the Microsoft Azure platform,
also called the Azure services: Windows Azure, Windows Azure AppFabric,
and SQL Azure. All three offer unique capabilities that provide a
complete array of services needed to build highly scalable and secure
A collection of virtual Microsoft operating systems that can run your
web applications and services in the cloud. For example, you can create
a web service that converts US dollars to Euros; then, you can deploy
the service on Windows Azure and allow it to scale as needed. Note that
Windows Azure can run .NET applications and other platforms as well,
Windows Azure AppFabric.
A set of services that provide core capabilities such as federated
identity for access control, and a service bus for a messaging-based
Microsoft's transactional database offering for cloud computing based
on Microsoft SQL Server 2008. For example, you can store your customer
database in the cloud using SQL Azure and consume customer data using
services deployed in Windows Azure.
shows a simplified corporate environment connecting to the Microsoft
Azure platform and consuming all three services. This diagram is overly
simplified, but it conveys an important message: Microsoft Azure is
designed to extend a corporate environment securely for web
applications, services, messaging, and data stores.
Figure 1. Microsoft Azure platform overview
1. Why Microsoft Azure?
One of the fundamental
questions that's frequently asked is, "Why?" Who's interested in
developing applications in Windows Azure in the first place? To answer
this question, let's look at the evolution of web platforms.
About 15 years ago, when the
public Internet was all about bulletin board systems (BBBs), Gopher
services, and $500 9600-baud modems, the question was, "Will the
Internet stick as a technology?" That question has been answered, but
many new concepts have grown since then, including web sites, hosting
centers, and SaaS.
This evolution relies on a common theme: decoupling.
BBSs decoupled public information from libraries; web sites decoupled
user interfaces from computers; hosting centers decoupled hardware from
a company's own infrastructure; and SaaS decoupled complex applications
from corporate computers.
Cloud computing on
Microsoft Azure is a natural evolution of computing flexibility in
which the actual physical storage and implementation details are
decoupled from the software solution. For example, deploying services
in Windows Azure doesn't require any knowledge of the machine running
the service or any of the core services (IIS version, operating system
patches, and so on). You may never know which machine is running your
software. Connecting to a Windows Azure server is performed through
logical names, just like connecting to SQL Azure.
The ability to
disassociate machines from data and services is very powerful in
itself. Although it's still an early-stage platform, Microsoft's Azure
environment allows multiple business scenarios to flourish, including
Developing web sites or services that have a tendency to grow and
contract over time provides potential savings opportunities because
cloud computing uses a pay-as-you-use model.
Short life span.
Development of prototypes or applications with short lifespans is also
attractive, such as event-registration sites. You can also build
development and test environments for remote teams.
Certain applications need to keep storage in a safe location but may
not require frequent access, or may require high availability.
Designing or modifying an application so that the data is stored
locally and in SQL Azure (or other data-storage formats) may make sense.
Small companies and ISVs.
Smaller companies that can't afford large and complex infrastructure to
start their business can take advantage of the financial and inherent
infrastructure benefits of Microsoft Azure. Independent software
vendors (ISVs) can also benefit from cloud computing. For example, an
ISV can use SQL Azure to store application logs or centralize reporting
features from multiple disconnected locations.
2. About Geographic Locations
In order to
provide high availability, Microsoft established regional data-center
operations that allow customers to select geographically dispersed
services. When you create your Azure servers, you need to specify which
geographic location the servers should be provisioned in. This feature
is called Windows Azure geolocation.
Initially, it may be
tempting to choose your company's geographic location for improved
performance. However, if the availability of your Azure services is
more important than response time, you may need to pick another
location. When selecting a geographic location, make sure to consider
Performance. When your data is closer to your users, network latency may be noticeably lower, improving customer experience.
If ensuring the availability of your cloud platform is important, you
may want to disperse your services and data across multiple regions.
Consider the type of information that will be stored in the cloud, and
ensure that you aren't bound by specific regulations and mandates that
may prevent you from selecting remote geographic locations.
At the time of this writing,
you can select from one of the following geographic locations, each of
which is supported by a regional data center:
North Central US
South Central US
In addition, you can create an affinity group
that lets you keep certain Azure services together. Such a group
creates a geographic dependency between Windows and data services
deployed in the Microsoft Azure platform. If Microsoft is obligated to
move a service to another geolocation for regulatory reasons, the
related services will likely move along. For example, if you develop an
Azure service that depends on a SQL Azure database, you may want to
ensure that they both reside in the same geolocation and that they
belong to the same affinity group.
Additional locations will be
added over time. As a result, you may need to reevaluate on a regular
basis whether a service is deployed in the most appropriate geographic
3. Storing Data in Azure
As you can imagine, cloud
computing is all about storing data in a simple yet scalable manner.
The Microsoft Azure platform doesn't disappoint and offers a variety of
storage models that you can choose from. This section summarizes the
four ways you can store your data in Azure; three of these approaches
are considered part of the Azure services.
provides an overview of the storage options and the available access
methods. The set of storage options provided by Windows Azure is
referred to as Windows Azure storage,
which includes blobs, tables, and queues. Windows Azure storage can be
accessed directly from a corporate environment using HTTP/S calls,
providing a simple hook into the Microsoft Azure platform. In addition
to using Windows Azure storage, consumers can make requests directly to
a SQL Azure database using ADO.NET or ODBC, because SQL Azure supports
the Tabular Data Stream (TDS) protocol that SQL Server uses. As a
result, applications and services connecting to a SQL Server database
can just as easily connect to a SQL Azure database.
Figure 2. Microsoft Azure data storage access
Following are further details of the four storage types:
Azure services storage. The Azure services offer three distinct storage models that are tailored to specific needs:
A named value-pair storage that allows you to store very large amounts
of data. This storage model includes automatic load balancing and
fail-over. It's called a table because you can store multiple values in
each row. However, this isn't a transactional storage mechanism; no
indexing or table joins are possible. Also, the columns defined in a
table have storage limitations. For example, a string data type is
limited to 64KB.
An interface to store files, with a maximum limit of 50GB of storage
for each blob. You can easily access blobs using a straight HTTP
request through a Representational State Transfer (REST)) call.
A highly available mechanism for storing messages for consumption by
other applications or services. A typical usage of queues is to send
XML messages. Certain limitations apply to queues, but you can access
queues through REST as well.
SQL Azure is a transactional database that provides familiar data
access through ADO.NET or other providers and gives you the ability to
manipulate the data using standard T-SQL statements. Databases in SQL
Azure are limited to either 1GB or 10GB, depending on the edition
Table 1 summarizes the current characteristics of these data-storage options available in the Azure platform.
Table 1. Storage summary in Azure
|Storage Mode||Maximum Size||Access||Format||Relational|
REST||Rows and columns||No|
10GB||ADO.NET||Rows and columns||Yes|