Group 2

Bernard SmithThomas LabordeHannah Prather

Fault Tolerance

Environment

Power

Topology and Connectivity

Servers

HurricanePreparedness

Network Edition

Guide

Hurricane Preparedness: Fault TolerancePower

EnvironmentSection 1: Fault Tolerance, Environment, and Power

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Hurricane Preparedness: Fault TolerancePower

EnvironmentData Protection Plan:

•Excessive Heat•Moisture•Break-ins•National Disasters

Prevention:

•Locked doors•Air conditioning•Maintained at constant humidity.

Power

Power Flaws:

•Surge•Noise•Brownout•Blackout

Fault ToleranceThe capacity of a system to continue performing despite an unexpected hardware or software malfunction.

Fault vs

Failure

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Hurricane Preparedness: Fault TolerancePower

Factors to consider in deciding which UPS is right

for you:

UPS (Uninterruptible Power Supplies)

3

2

1

Generators

4

Amount of Power Needed (volt-amps)

Period of time to keep a device running

Line Conditioning

Cost

OnlineStandby

What type of

generator do we

need? Diesel?

Steam? natural

gas? liquid propane

gas?

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Hurricane Preparedness: Fault TolerancePower

Figure 14-2 UPSs and a generator in a network design

Generators

typically are

combined with

UPSs to ensure

clean power is

always

available

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Hurricane Preparedness: Fault TolerancePower

EnvironmentSection 2: Topology and Connectivity

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LAN- a star topology

WAN- full-mesh topology

SONET

T1 link

Hurricane Preparedness: Fault Tolerance

Contact Internet

Service Provider

and establish a

Virtual Private

Network

Hurricane Preparedness: Fault TolerancePower

Topology

6

Determine your

network’s needs

Supply multiple

paths for the

data

Concerns:• Capacity• Scalability

Hurricane Preparedness: Fault ToleranceHurricane Preparedness: Fault TolerancePower

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Connectivity

Internet

• Failover

• Hot swappable

• Load balancing

With many

devices

connected in

one network,

leaves more

room for failure

Hurricane Preparedness: Fault TolerancePower

EnvironmentSection 3: Servers

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Advantage: each

server can provide

its own data

processing

-always ready to

take over for failed

server

-reduces cost

-improves

performance

Hurricane Preparedness: Fault ToleranceHurricane Preparedness: Fault TolerancePower

Server Mirroring

Redundancy ensures fault tolerant servers

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Clustering

Servers

• NICs• Processors• Hard disks

• One device duplicates the activities of another

Advantage:

servers involved

do not have to be

next to each other

Disadvantage:

time consuming

• Links multiple servers together to act as a single server

Hurricane Preparedness: Fault TolerancePower

EnvironmentSection 3: RAID

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Hurricane Preparedness: Fault TolerancePower

Disk 1 Disk 3Disk 2 Disk 4

Disk Controller

RAID drive

64 KB

64 KB

128-KBfile

RAIDRedundant

Array of

Independent

Disks1. A collection2. Single disk Failure3. Increase Storage4. Better Disk Performance

Level 0

1. Simple2. 64 bit blocks3. No Redundancy4. Multiple5. Best Performance

AKA Disk

Stripping

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Hurricane Preparedness: Fault TolerancePower

Disk 1 Disk 3Disk 2 Disk 4

Disk Controller

RAID drive

128 KB

128 KB

128-KBfile

- Disk - mirro

ring

- Failed disk =

Auto switch

- Costly – identical

disks

Level 1

Software is

taxing on the

CPU

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Hurricane Preparedness: Fault TolerancePower

Disk 1 Disk 3Disk 2 Disk 4

Disk Controller

RAID drive

1 KB

.33 KB

1 KB

.33 KB

1 KB

.33 KB

Parity

Parity

File 1(3 KB)File 2(1 KB)

RAID Level 3- Disk Stripping,

Error Correction

Code algorithm

- Parity, integrity

of data

- Sum of data plus

parity = odd or

even

- Written then

read

- Parity on one

disk- could fail

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Hurricane Preparedness: Fault TolerancePower

-Most Popular

-Parity with error

checking

-Fault Tolerance

Failed disk,

software

Disk 1 Disk 3Disk 2 Disk 4

Disk Controller

RAID drive

4 KB

4 KB

4 KB

4 KB

4 KB

4 KB

File 1(12 KB)

File 2(16 KB)

Parity Parity

Parity

Parity

4 KB

Hot Spare – part of

system, ready to

go

Cold Spare – not

installed

RAID Level 5

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Hurricane Preparedness: Fault TolerancePower

EnvironmentSection 4: NAS & SANS

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Hurricane Preparedness: Fault TolerancePower

NAS (Network Attached Storage) SANs Storage Area Networks

1. Connected to a Network2. Optimized for saving

and serving files

Must have a file server to interact

1. Communicates Directly2. Mesh Topology3. Most Fault Tolerant 4. Fiber Optics

Multiple storage

devices connected

to multiple servers

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Hurricane Preparedness: Fault Tolerance

Any

questions?

Call Kari

Walters for

more

information

225-555-555

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