Databases Reference
In-Depth Information
Chapter 1
Getting Started with SQL Database
Born only a few years ago, cloud computing is capturing the imagination of startups and large corporations alike. In
its simplest form, cloud computing is an evolution of traditional hosting models; as such, it isn't necessarily a new
technology. Rather, it's a new concept that offers new opportunities and challenges not found in existing business
models. Much as agile programming provided a new software development paradigm, cloud computing provides a
new delivery model for Internet-based solutions. And when it comes to relational data, Microsoft delivers the only
cloud database available today: Windows Azure SQL Database.
Introduction to Cloud Computing
Let's begin with what cloud computing has to offer compared to traditional hosting services. The following
capabilities are generally expected from large cloud-computing providers:
•
Automatic and unlimited scalability.
The promise that if your service needs more resources,
more resources will be provisioned automatically or with limited effort. For example, if you
deploy a web service, and you experience a sudden surge in processing needs, your services
will automatically expand to additional servers to handle the temporary surge and contract to
fewer servers during off-peak activity.
•
Unassisted deployment.
The promise that if you need to deploy additional services or
databases, you don't have to call anyone or open a service ticket. The cloud service provider
will give you the necessary tools to perform self-service.
•
Built-in failover.
The promise that if one of your servers fails, no one will ever notice. For
example, if the server on which your service is installed crashes, a new server immediately
takes over.
•
Grow as you need; pay for what you use.
The promise that you only pay for the resources you
use. For example, if your service experiences a sudden surge in processing needs for a day, but
it scales down to its usual usage for the rest of the month, you're only charged marginally more
than usual for the temporary surge.
Cloud providers deliver on those promises in different ways. For example, the promise for automated and
unlimited scalability comes in different flavors depending on the service being considered. A Web Service layer will
be easier to scale than a database layer. And scaling a Web Service layer with Amazon will be different than with
Microsoft. As a result, understanding how cloud providers implement these capabilities can be important in your
application design choices and support operations.
The fact that each cloud provider implements its services differently has another, more subtle implication.
Switching cloud providers can be very difficult. If you design your application in a way that takes advantage of
Amazon-specific services, adapting your application for the Azure platform may be very difficult. As a result, you
