Datasheet

CHAPTER 1 AN INTRODUCTION TO DESIGNING VMWARE ENVIRONMENTS

environment, the functional requirements that derive from that reason will affect a number of

different areas:

u The server hardware selected needs to be capable of running the virtual machines conﬁ g-

ured with enough resources to run Microsoft Exchange Server 2010.

u The virtual machines that will run Exchange will, most likely, need to be conﬁ gured with

more RAM, more virtual CPUs (vCPUs), and more available disk space.

u The conﬁ guration of Exchange Server 2010 will affect cluster conﬁ gurations like the use

of VMware High Availability (HA), VMwareDistributed Resource Scheduler (DRS), and

VMwareFault Tolerance (FT).

u The cluster conﬁ guration, such as the ability (or inability) to use VMware FT, will

in turn affect the networking conﬁ guration of the VMware ESX/ESXi hosts in the

environment.

u Operational procedures need to be included in the design as a result of the use (or lack of

use) of features like VMwareHA, VMwareDRS, and VMwareFT.

This list can go on and on, but at this point you should get the idea. The functional require-

ments affect almost every decision point in every facet of the design; as a result, they lie at the

core of creating a VMware vSphere design. Any design that doesn’t directly address the orga-

nization’s functional requirements is a poor design, and the implementation won’t be a success.

Any consultant or VMware vSphere architect who attempts to design a vSphere environment

without knowledge of the functional requirements will fail. After all, the functional require-

ments are the targets the design is aiming to hit; how can the design hit those targets if the

targets aren’t known and understood?

Interestingly, although the functional requirements directly affect the decision

points — things like what servers to use, the form factor of the servers, the number and type

of network interface cards (NICs), and so on — these decision points also affect the functional

requirements. An inherent interdependency exists between the functional requirements and the

decisions, as shown in Figure 1.3.

Figure 1.3

Functional require-

ments and design

decision points are

interdependent.

Functional

Requirements

Decision

Points

NOTE You’ll likely see the term design constraints used in formal VMware design documenta-

tion. A design constraint is a decision point—such as the type of server you’ll use, the type of

storage you’ll use, or the way in which you’ll connect to an existing network—that has already

been made and can’t be changed. Because this decision point can’t be changed, it constrains

your design.

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