Information Technology Reference
In-Depth Information
The industry has responded to these concerns by facilitating automation of sys-
tem and VE provisioning and updating. The newly introduced tools ease the tasks
of standardization, security checks, and detailed compliance reporting. Further,
automated workflow tools reduce opportunities for error, reduce the administra-
tive burden, and reduce the elapsed time to provision or update systems.
9.1.1.5 Manage
Ready availability of up-to-date data about VE configurations and health re-
duces the burden of managing systems. Although consistent, holistic monitoring
certainly reinforces proactive management, exceptions are still bound to occur.
Having baseline data about activities and performance can simplify and drasti-
cally shorten the time needed to diagnose and resolve a problem.
Newer DCM tools support new methods of optimization in the data center. In
the past, people avoided activities such as load-balancing workloads across servers
because of the difficulty and risk involved. Virtualization provides a layer of sepa-
ration between the hardware and the VE. This structure makes redeploying a VE
(moving it to a different computer) easier because the VE is mapped to a hardware
abstraction that is commonly supported on many computers.
Armed with performance data, target performance criteria, and the current as-
signment of VEs to computers, it is possible to consider regularly balancing the load
of VEs across the data center. A detectable service outage may not be necessary.
This process is simplified by consistency of hardware across the data center. With
most virtualization technologies, a VE can run on only one CPU architecture, and is
usually limited to specific instances of an architecture. In most cases, a pool of com-
puters of similar architecture is grouped so that they are managed as one entity. VEs
can be moved within the pool to balance the workload. Guidelines for determining
which systems are similar enough to be pooled together and for making assignments
of VEs to pools are given in Chapter 7, “Choosing a Virtualization Technology.”
Despite the promise inherent in this technology, caution should be exercised
when implementing VE migration. This functionality is relatively new to the com-
puter industry, and many people do not have experience with it. Also, few software
developers have considered the impact of migrations. Many do not support their
applications if VE migration is used.
The business value of VE migration is discussed further in the next section.
Operational Flexibility
As mentioned earlier, virtualization has led to a new way of viewing a data center
and its systems and workloads. Ideally, quick and easy deployment of workloads
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