Datasheet

Part I: Ready, Set, Go with VMware Infrastructure 3

Stage 1: Capacity planning

and return on investment

Start off by determining how much capacity you need today as well as how

much growth you anticipate. Today’s needs, obviously, determine what

hardware you have to buy to get started. Your anticipated growth needs

determine how much you will save by not purchasing physical servers.

Even without taking the electricity, cooling, and space savings into consider-

ation, you can usually find a ROI just by the savings generated through not

buying future servers and their associated hardware maintenance contracts.

For example, I designed my system with a minimum virtual-to-physical ratio

of 15:1. As I need more capacity, I can add a single physical machine and

build at least 15 more virtual servers.

Think about the math behind that for a moment: You can spend $12,000–

$15,000 on each server 15 times — or just once. Additionally, you can spend

roughly $500–$1,000 per year for maintenance contracts 15 times — or

once. Say that you’re going to roll out 15 servers ($12,000 each for a physical

server) in a year; also assume each server costs $500 per year for a mainte-

nance contract. And, say that the expected lifetime is five years. Look at the

following three options:

Plan Expenses Total Costs

Physical infrastructure Hardware: $12,000 × 15 $180,000

Maintenance: $500 × 15 × 5 $37,500

$217,500

Adding to an existing virtual Hardware: $12,000 $12,000

infrastructure Maintenance: $500 × 5 $2,500

$14,500

Building a two-node virtual N+1 fault-tolerant server $24,000

infrastructure from scratch hardware: $12,000 × 2 $120,000

SAN hardware $7,500

Maintenance: $500 × 3 × 5

$151,500

By using N+1 you have

enough excess capacity to

absorb a single system

failure without an outage.

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