Database Reference
In-Depth Information
associated set of VMs. For example, in an environment with an application server layer,
middle layer, and database backend, the template could include three VMs, with all the
associated security and interconnects. With virtualization, that golden template we have
all strived for as DBAs is now possible. Yes, Database as a Service is possible.
Hardware Refresh and Database Virtualization
When we virtualize, we are no longer operating in a world where one physical server
equals one application. We no longer live in a world where we have to understand all
the nuances of a particular suite of hardware. Before virtualization, the operating
environment would look something like
Figure 2.7
.
Figure 2.7
Before virtualization.
In the traditional (nonvirtualized) world, we would have a single operating system
loaded onto a single physical server. Also, the SQL Server database would be on a
physical server that is not a shared resource. The server would exist for one purpose—
to support the Microsoft databases running on the server; it was never meant to be a
shared resource.
In this physical server, the software and hardware would be tightly coupled. An upgrade
of the server or any of its components has to be handled carefully because it could affect
how particular applications loaded on the server work. In the case of a complex
application such as a SQL Server database, this process of upgrading could take weeks
of planning. As we go through the process of testing the database and applications
against the new hardware configuration, we could spend weeks just to determine the
proper patches needed so that everything works correctly post-upgrade.
