reading

Table of Contents

Introduction

About This Book

Foolish Assumptions

Conventions Used in This Book

How This Book Is Organized

Icons Used in This Book

Part I: SAN 101

Chapter 1: The Storage Area Network

Defining a SAN

Fiber versus Fibre

How a SAN Makes Computing Different

Understanding the Benefits of a SAN

Finding Out Whether a SAN Is Right for You

Who should use a SAN?

Who should not use a SAN?

Dissecting a SAN (The Four Ps)

The Parts of a SAN

The host layer

The fabric layer

The storage layer

Storage arrays

The SAN Protocols

The SAN Players

The SAN Platforms

Applications that benefit from a SAN

Applications that require a SAN

Chapter 2: SAN Building Blocks

SAN Components and How They’re Used

The Host Layer

Host bus adapters

Gigabit gadgets: GBICs and GLMs

The Fabric Layer

Understanding storage fabrics

SAN hubs

SAN switches

Data routers

Cables

Cable-connector types

SAN ports and port naming

Basic SAN port modes of operation

Protocols used in a Fibre Channel SAN

The Storage Layer

Storage arrays: Storing your data

Explaining Redundant Array of Inexpensive Disks (RAID)

RAID benefits

RAID types

Logical Unit Numbers (LUNs)

Understanding storage-array classification

Modular versus monolithic

Monolithic (Enterprise)

Modular (Departmental)

Why Cache memory makes a difference

Chapter 3: What Makes a SAN Go

Networking Basics

Moving Data at the Speed of Light

Bandwidth

Fibre Channel Protocols

The arbitrated loop

Loop addressing

The Switched Fabric

The fabric protocol

Fabric addressing

Chapter 4: What Makes a SAN Stop

Discovering What Causes SAN Problems

Preventing Poor SAN Design

Bandwidth

Too much distance between components

Excess latency

Congestion

Over-subscription

Using the Right Cables in the Right Way

Avoiding connection issues

Macro- and micro-bends, and the patch panel pain

Cable labeling

Choosing the right host bus adapter for your computer

Going with a single vendor

Mixing switch vendors

Part II: Designing and Building a SAN

Chapter 5: Designing the SAN

Basic SAN Designs: Understanding the Layers

Point-to-Point Topology

Arbitrated Loop Topology

Cascading hubs

Loop of hubs

Creating resilient hub networks

Fault-tolerant loops

Switched Fabric Topology

Types of SAN switches

Choosing which switches to use

Using the right bandwidth for the job

Trunking and what it’s used for

Basic Fabric Topologies

Dual switches, the SAN fabric building block

Loop-of-switches topology

Meshed fabric topology

Star topology

Core-edge topology

Understanding Zoning

The parts of a zone

Types of zoning

Zone alias names

Initial Switch Setup

Setting up a Brocade switch

Setting up an original McData (Brocade) director switch

Best Practices — Tips from the Trenches

When to choose a director-class switch

Standardize on a single vendor’s switches

Standardize your firmware versions

Standardize your HBA drivers

Use unique zone alias names

Using storage from multiple vendors

Always use two fabrics

Chapter 6: SANs and Disaster Recovery

How Much Downtime Can You Afford?

Gathering the data for a disaster-recovery plan

Create a detailed plan that meets your requirements

Recognizing the Importance of Distance, Bandwidth, and Latency

Distance

Bandwidth

Latency

Choosing the Recovery Site

Existing facility

Co-location facility

Choosing Where to Run the Data Replication Process

Host-based data replication solutions

Appliance-based data replication solutions

Array-based data replication solution

Shipping tapes as a solution

The Importance of Testing

Chapter 7: Putting It All Together

Building a SAN by Hand

The SAN Plan

Fabric Zoning 101

LUN security

Setting Up the SAN

Keeping good notes

Setting up the switches

Preparing the Servers

Loading the driver

Customizing the HBA card’s configuration

Planning the HBA connections

Configuring the Array

The hardware

RAID setup

Plugging Things In

Configuring the Zones

Mapping the zones first

I’m zoning out . . .

Back to the Servers: Did It Work?

Unix servers

Windows system

iSCSI, You SCSI, We All SCSI

Initiators and targets

IQN: iSCSI qualified name

SCSI Name Service

Data domains

Getting started with iSCSI

Getting serious with iSCSI

Data Migration

Network migration

Backup/restore migration

Disk-to-SAN migration

Part III: Using Advanced SAN Features

Chapter 8: Networking SANs

Defining a SAN Island

Connecting SAN Islands

Disk/data sharing

Data copying

The Storage WAN, MAN, and SWAN

Using the network only for storage management

The storage SWAN

Choosing and Using SAN Extenders

Choosing the Correct Link for the Job

IP connections

OC-type connections

Reducing Costs with Compression, Data De-duplication and WAN Tuners

Compression

De-duplication

WAN tuners

SAN Connection Protocols

FCIP: The SAN tunnel

iFCP: The SAN gateway

Stretching the SAN (The Rubber-Band Approach)

Using Connected SAN Islands (The Two-Rubber-Bands Approach)

Using a SAN as Network Attached Storage

iSCSI: An Alternative Method

Chapter 9: SAN-Based Backup

Understanding Backup

Understanding SAN Backup

The backup window

Tape drives

Tape libraries

Backup policy

Choosing a Backup Solution

Integrated tape drive in each server

Backup over a corporate LAN to a tape drive connected to an independent backup server

Backup over corporate network to robotic tape library connected to an independent backup server

LAN-less backup to shared tape library over SAN

Serverless backup to shared tape library through SAN

Disk-to-disk backup

Image copy and snapshots in the SAN

SAN data replication/remote backup

Determining How Long a Backup Will Take

Determining backup speeds

The formula for backup

Chapter 10: Mirror, Mirror: Point-in-Time Copies

The Uses of Point-in-Time Technology

Make backups

Make corruption-recovery images

Save space

The possibilities are endless

Complete versus Metadata Copies

Which PiT Type Should You Use?

Creating a PiT Copy

Managing Your Point-in-Time Copies

Pair up your volumes

Create the pairs

Splitting the mirror, snapping a copy

Doing a resync: Refresh and restore

I need my data now!

Using a PiT copy

The Finer Points of PiT

Guideline #1: Understand when to snap a copy

Guideline #2: Keep your PiT pairs separated

Guideline #3: Use the right disk storage for PiT copies

Questions to ask your SAN vendors

Part IV: SAN Management and Troubleshooting

Chapter 11: Approaches to SAN Management

Management: From Simple Networking to SANs

SAN Management from the Ground Up

Start small; think big

Documentation is key

Cable Management: Spaghetti, Anyone?

Physical cable management

Logical cable management

Labeling Your Cables

Data center coordinate system

Standard naming convention

Documenting the cable arrangements

Using a SAN Management Framework

Working with SAN management software

Communicating in a common language

Speaking the language yourself

Putting everything together

What SAN Management Gives You

A bird’s-eye view of your network

Agent-based management

Health monitoring

Records of events

Change management

Predictions of problems

Streamlining SAN Administration

Step-by-step administration

Using a framework

Automating Your System: “SAN? Do You Read Me, SAN?”

Backing up

Managing database storage

Providing a Service Level Agreement

Simple versus complex SLAs

Setting service levels

Building a Storage Management Team

SAN architects

SAN engineers

Monitoring team

SLA and performance specialists

Provisioning staff

Planning for the future

Common responsibilities

Chapter 12: Troubleshooting SANs

The Best Method: Prevention

Troubleshooting Methodology

Go with what you know

Elementary, my dear Watson

Didn’t read the manual, did you?

Build a golden configuration

Typical Problem Types

Obvious problems

Phantom problems

Continuous problems

Catastrophic problems

Example Scenarios

Scenario #1

Scenario #2

Scenario #3

Part V: Understanding the Cool Stuff

Chapter 13: Using Data De-Duplication to Lighten the Load

Understanding Data De-Duplication

Benefits of data de-duplication

How de-duplication works

Data De-Duplication in the Datacenter

The de-duplication vendors

How data gets de-duplicated

In-band versus out-of-band data de-duplication

Using Data De-Duplication in a SAN

Files: Honey, I shrunk the files

Blocks: Been there, stored that

What about hash collisions?

Why Data De-Duplication Is Important

When to Use Data De-Dupe (And When Not To)

Applications for which data de-duplication makes sense

Applications for which data de-duplication doesn’t make sense

De-Duplication in Action

Chapter 14: Continuous Data Protection

Understanding What Continuous Data Protection Is

How CDP Makes Storage Work Like a Database

CDP data journaling

Splitting the writes

CDP makes everything different

Sizing a CDP journal

Best Practices for Storage When Configuring CDP Solutions

The Truth about Near CDP and True CDP Solutions

Example 1: Recovering a database with traditional backup

Example 2: Recovering a database from a snapshot

Example 3: Recovering a database using near CDP

Example 4: Recovering a database using true CDP

CDP versus Snapshots

Using CDP to Eliminate Backups

Using CDP to Simplify Recovery and Reduce Costs

Knowing Your CDP Vendor

Chapter 15: Everything You Ever Wanted to Know about Virtualization

Understanding What Virtualization Is

Exploring the Types of Virtualization

Implementing Virtualization in a Datacenter

Server virtualization

Storage virtualization

In-Band versus Out-of-Band Virtualization

In-band virtualization

Out-of-band virtualization

The Virtualization Vendors and Where They Play

Host-based storage virtualization vendors

Fabric-based virtualization storage vendors

Storage-array-based virtualization

Part VI: The Part of Tens

Chapter 16: Ten Reasons to Use a SAN

You Want Better Disk Utilization

You Need a Good Disaster Recovery Solution for Multiple Applications

You Need Better Availability for Your Applications

You Need More Storage Room

Backup Is Taking Too Long

You’re Focusing on Server and Storage Consolidation

You’ve Been Tasked to Save Your Company Money

You Need to Manage Storage for Many Locations from a Central Site

You Need to Decrease IT Management Costs

You Need Better Performance for Your Applications

Chapter 17: Ten Reasons NOT to Use a SAN

You Need Larger File Servers

You Only Have a Few Inexpensive Servers

You Want to Save Your Company Money This Year

You Want to Use the Latest and Greatest Solutions Available

You Need a Disaster-Recovery Solution for a Single Application

You Want a SAN but Don’t Have the Budget

You Use Gigabit Ethernet on Your LAN

Everything Already Runs Fine

You Need to Back Up Multiple Remote Offices over Slow Links

You Need to Replicate Your Data for Disaster Recovery but Can’t Afford Fast WAN Connections

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Christopher Poelker has been in the field of computer technology since 1974. Chris was an electronics engineer in the U.S. Army, and tried to stay out of trouble by hiding in tanks while installing laser range finders and computer-aided ballistic trajectory systems. After leaving the service, Chris went to school in New York City at good old Control Data Institute and was hired as a field engineer by Digital Equipment Corporation. In his spare time, Chris started his own software company, developed databases, and became a Microsoft MCSE and instructor. Chris worked for Digital for 18 years until it was bought by Compaq, where he stayed on as a StorageWorks systems engineer until joining Sun Microsystems in 2000. Chris left Sun to become a consulting storage architect for Hitachi Data Systems and became the district storage manager for HDS in New York City. In 2006, Chris left HDS for FalconStor software, where he now works as the Vice President of Enterprise Solutions. Chris has designed and implemented storage networks for many of the Fortune 100 companies in the U.S. and around the world. In his spare time, Chris sometimes speaks at industry forums, writes magazine articles, and has acted as the SAN expert at SearchStorage.com.

Alex Nikitin, currently a systems expert at HBO, has logged in 15 years in the Information Technology industry. Alex has worn many hats in this industry, ranging from application programmer and network administrator to the ultimate responsibility over large server farms, and storage and backup solutions for some of the world’s top financial and pharmaceutical companies. Alex and Chris worked together at Hitachi Data Systems in New York, where Alex was the “go to” guy for difficult storage designs and implementations. Prior to joining HDS, he also spent time growing the install base of Storage Area Networks as a Professional Services Consultant for EMC Corporation, implementing SAN solutions for various companies, large and small, on Windows NT/2000, Solaris, HP/UX, AIX, and Linux platforms. Seemingly always cast in a storage-centric capacity, his career has focused on caring for and reliably delivering vast amounts of storage to his user community.

Christopher Poelker: To my sister Nancy, whose love and friendship meant the world to me.

Christopher Poelker: I would have never been given the chance to write this book if it weren’t for my friends at TechTarget, who used to run the SearchStorage.com Web site: Michelle Hope and Maryann Tripp. These two wonderful women were the reason I was introduced to Melody Layne and Susan Christophersen of Wiley Publishing, who made the first book possible, along with Teresa Artman, who spent many a long night copy-editing the manuscript and making up for my horrible writing skills. (I should have paid closer attention during eighth-grade English!) For this second edition, I would like to thank Kyle Looper and Kim Darosett for their patience during deadlines when my day job was getting in the way of keeping this edition on track.

I’d also like to thank my partner in crime and co-author, Alex Nikitin, who again saved my marriage and my duty as a father to my children by taking over some of the load and helping me crank out some of these chapters. Alex is one of the best storage guys I have ever had the privilege of working with.

Thanks also need to go this time to FalconStor software, for letting me proceed with this project and letting me play hooky now and then to crank out a chapter or two. Thanks to ReiJane Huai, Wendy Petty, Wayne Lam, Alan Chen, Tom Strumpf, Bruce Sasson, Joanne Ferrara, and everyone else at FalconStor who filled in or helped me out to give me time during the writing of this book.

Special thanks to all the folks who taught me most of the things I know about storage: my brothers, Lenny Poelker and Greg Poelker, who are a heck of a lot smarter than I! Also to my mentors: Wayne Lam, Wai Lam, Stanley Qin, Irving Moy, David Shyu, Cartic Vengkatraman, Gene Chesser, Steve Sicola, Paul Kruschwitz, Jimmy Wu, Raymond Tong, Paul Mitchell, Mike Mendola, Jo McCausland, John Lallier, Nick Sinish, Brian Rice, Steve O’Rielly, Catherine Brown, Frank Cizin, Leonard Hayward, Charlie Mulrooney, Paul Poon, Don Thatcher, Tony Merschdoff, Jeff Sinisgalli, John Fonseca, Marty Citron, Al Catalano, Tom Lindemann, Roland Song, Pierre Dansereau, Mike Pierro, and most of all, Kevin Shumacker, whose help over the years I could never repay. Thanks to Ken Garnau, Nancy Berliner, and Charlie Santana for help with the mainframe stuff, and everyone I ever met from Brocade/McData, and Emulex.

Tom Clark and Robert Stout, Nancy Jennings, and John Dorl from the original Nishan systems were a big help with helping me figure out SAN extensions, (especially Tom’s books!), and Mark Farley’s book was the first I read on SAN and still is one of the best. (I guess I learned things the hard way, by just doing it.)

Finally, thanks for the support of my family: Deborah, my wife, for being a single mother again while I was writing the book, and of course, my children Cole, Chris, and Rachel for all their support and being the wonderful people they turned out to be.

We’re proud of this book; please send us your comments through our online registration form located at www.dummies.com/register/.

Layout and Graphics: Samantha Allen, Reuben W. Davis, Melissa K. Jester, Christine Williams

Introduction

Welcome to Storage Area Networks For Dummies, 2nd Edition! The first edition was the book we wish was around when we were trying to learn about this stuff! We tried to take a fairly mundane topic and make it a fun read so you could get up to speed on storage networking as quickly and painlessly as possible. This second edition is written in the same spirit as the first.

When the first edition was written in 2003, very few books on storage area networks (SANs) were available. The books that were available were very narrow and extremely technical in focus. They were about as fun to read as the directions for setting up a DVD player. Although more books about storage networking are available now, most are still very technical and about as fun to read as the U.S. tax code (nothing against accountants here!).

Over the years, this book has become the standard bearer in keeping the subject concise, simple, and fun, and has now been updated to include all the new cool stuff and changes that have occurred since the original printing. Let’s face it — most folks typically look for a fast and easy way to get information; you want the information you need to know, and not everything there is to know, so this second edition uses that same point of view common to all of us poor slobs who need to make a SAN work with no budget, no training, and no time. So don’t worry, be happy — and just have some fun!

About This Book

The mission of this book is to help you find your way around while exploring the topic of storage area networking. The book is dedicated to individuals who, for better or for worse, have been tasked with designing, implementing, configuring, or troubleshooting a storage area network. We hope that the information here will enable both the beginner and the moderately expert storage professional sort through the ins and outs of a SAN. We use familiar language to demystify the technology and translate the jargon as necessary. You’ll discover how to choose the right hardware for the job, design a SAN by using the best practices in the industry, connect everything to make it work, and troubleshoot the SAN to fix problems when they occur.

You also get to delve into the hard stuff — the stuff that many companies pay expensive consultants for (who have usually just read a book like this just before they were hired!), so be brave, and we’ll do our best to make this painless. If you want to understand what a SAN is and what it does, you’ve come to the right place. Everything you should need (or want) to know about storage area networks is here in one location.

Foolish Assumptions

We have one or two foolish assumptions about you, the reader of this book:

You are responsible for or have worked with computer storage before.

You might want to continue working in that field of endeavor.

You want to find an easy way out of your networking storage problems so you can get home and play video games, watch TV, and drink beer with your friends.

We also assume that you don’t want to become an instant expert. You want to know just enough to be able to speak intelligently on the subject matter but also know when it’s time to call in an expert.

This book tries to you get past all the little details that get in the way of understanding a subject by using a real-world approach. We didn’t create the technology; we just know how to make it work because we’ve been in the field for more years than we care to say. This book tries to impart just enough good info to help you make your stuff work — and to understand enough to know when someone is misleading you or trying to rip you off. The best defense is a good offense.

Conventions Used in This Book

We want you to understand all the instructions in this book, and in that spirit, we’ve adopted a few conventions.

When you hit a chapter in which we ask you to do something, you will be prompted by a numbered list. The numbers in the list are the order of the steps that you need to take to accomplish the task at hand. Just follow the steps listed, and everything should be just fine. If you need to enter something on the keyboard, we ask you to type it. If you need to use your mouse, we ask you to click it. That’s all there is to it.

How This Book Is Organized

This book is designed as a reference, so you don’t have to read the book cover to cover. Just look in the Table of Contents to find the topic you’re interested in and start reading. If you’re unsure of some of the acronyms you’ve been hearing out there, check out the Cheat Sheet at the front of this book for easy reference.

The book is organized in seven parts.

Part I: SAN 101: This part covers the basics of storage area networks, including what you need to know if you’re going to buy a SAN, build one yourself, or have someone build it for you.

Part II: Designing and Building a SAN: This part of the book handles all the fun stuff, such as how to add more storage to your servers and how to connect everything and get it running. It also covers what you need to know if you already have a SAN in place or need to know how to use it or set it up properly.

Part III: Using Advanced SAN Features: If you’ve always wanted to know what the heck a snapshot copy was, this is the place to find out. This part also covers advanced topics such as backing up your data, which will help you get more bang for your buck out of your SAN.

Part IV: SAN Management and Troubleshooting: Every now and then, something goes bump in the night. This part shows you how to manage and troubleshoot problems when they occur as well as how to avoid having to face those problems in the first place.

Part V: Understanding the Cool Stuff: This part covers the cool new advances in storage area networking since 2003, such as storage virtualization, data de-duplication, and advances in data protection and replication such as Continuous Data Protection (CDP). You find out how to use these technologies to help you save money and become more productive and better prepared when trouble happens.

Part VI: The Part of Tens: This part includes ten reasons to use a SAN and ten reasons not to.

We’ve also provided a bonus chapter titled “Outsourcing SAN Solutions” that you can download from the book’s companion Web site at www.dummies.com/go/sanfd2e.

Icons Used in This Book

To help you get the most out of this book, we’ve placed icons here and there. Here’s what the icons mean:

Next to the Tip icon, you can find shortcuts and tricks of the trade to make you more productive without even realizing it.

Where you see the Warning icon, tread softly and carefully. It means that we’ve been burned by this already and don’t want you to have to learn the hard way, as we did.

Stuff marked with the Remember icon is like jotting a note to yourself in a class. Make an effort to bend the ear of the page so that you don’t forget it.

Okay, we probably put too many of these icons in the book. But what the heck . . . sometimes trying to explain this stuff is like writing a book on Brain Surgery For Dummies. We need to point out the details at times so you don’t end up with a migraine.

Storage Area Networks For Dummies®, 2nd Edition

Storage Area Networks For Dummies^®, 2nd Edition