Database Reference
In-Depth Information
processors. An emulator would not be able to take advantage of the embedded
virtualization assist instructions, which manufacturers such as Intel and AMD have been
building into their processors for over 10 years, that help accelerate the performance of
vSphere.
When you first create a VM, you must load an operating system on it, just like you
would with a physical server. Without the operating system being loaded on the virtual
machine, it is of little or no use. The same applies to your physical server. Without an
operating system loaded onto it, the physical server is of little or no use.
It's important to understand that when programs are loaded onto the virtual machine,
they then execute in the same way they would on a nonvirtualized infrastructure. The
guest operating system provides access to resources such as CPU, memory, and disk in
the same way an operating systems does in a nonvirtualized infrastructure. The
difference is that the hypervisor is providing those resources to the guest operating
system, not the physical server itself.
Note
A virtual machine is a software-based partition of a computer. It contains
an operating system. The many applications running on the VM, such as a
SQL Server database, execute the same way they would on a physical
server.
Applications such as your SQL Server databases run in a software-based partition the
same way they would run in a nonvirtualized infrastructure. The core tenants of
virtualization include the following:
Partitioning
—The ability to run multiple operating systems on one physical
machine. Also, the ability to divide resources between different virtual machines.
Isolation
—The ability to have advance resource controls to preserve
performance. Fault and security isolation is at the hardware level.
Encapsulation
—The ability to move and copy virtual machines as easily as
moving and copying files. The entire state of a virtual machine can be saved to a
file.
Hardware independence
—The ability to provision or migrate any virtual
machine to any similar or different physical server.
As a DBA, these are important points to keep in mind as you manage the database.
Paravirtualization
Some other vendors decided to implement paravirtualization. To quote Wikipedia,
