Compaq StorageWorks 4000 - RAID Array, StorageWorks 4000 White Paper

White Paper

June 1999
ECG02030699A

Prepared by ECG Technology
Communications Group

Compaq Computer Corporation

Contents

Understanding Fibre

Channel Transmission .............. 3

Understanding Fiber Types....... 4

Connection Components .......... 5

Hubs........................................ 6

Gigabit Interface Converters..... 6

Fibre Channel Cables and

Connectors.............................. 7

Interconnecting System

Components.............................. 8

Overview of System

Components............................ 8

RAID Array 4000

Configurations.......................... 9

Using Infrastructure Cabling....11

Compaq StorageWorks
RAID Array 4000 Using

Infrastructure Cabling..............13

Testing......................................14

Test Specifications..................14

Handling Fiber and Fiber

Connectors...............................15

Acknowledgments and

References................................15

Understanding Compaq
StorageWorks RAID Array 4000
and Infrastructure Cabling

Abstract: Compaq StorageWorks RAID Array 40001 (RA4000)
storage solutions shatter distance, connectivity, capacity, and
bandwidth limitations of small computer systems interface (SCSI)
technology. RA4000 allows highly scalable, high-performance
storage solutions for the most demanding applications. While SCSI
technology continues to satisfy the needs of many applications,
inherent input/output (I/O) and physical limitations prevent SCSI
technology from satisfying all of the expanding needs of enterprise
storage. Compaq believes that the RA4000 is the best interconnect
technology choice for future storage solutions and is committed to
delivering enterprise storage solutions based on this technology.

This paper describes Fibre Channel transmission and the cabling and
components used to assemble the RA4000 system. It also describes
how and when infrastructure cabling might be used.

If plans for a Fibre Channel storage solution include using
infrastructure cabling, a company that provides installation and
testing services can be helpful, even necessary, to determine
appropriate cabling to meet data transmission rate and distance
requirements. See Acknowledgments and References later in this
document.

Note: Not all Fibre Channel configurations require connection to
infrastructure cabling. It is common to have all system components
located near each other, eliminating the need for infrastructure
cabling. This paper includes examples of RA4000 configurations
with and without infrastructure cabling.

For more information on Fibre Channel technology, refer to the
Compaq website:

www.compaq.com/products/servers/storage/fibre.html

1

RA4000 was known as the Fibre Channel Storage System.

Understanding Compaq StorageWorks RAID Array 4000 and Infrastructure Cabling 2

ECG02030699A

Notice

The information in this publication is subject to change without notice and is provided “AS IS” WITHOUT
WARRANTY OF ANY KIND. THE ENTIRE RISK ARISING OUT OF THE USE OF THIS
INFORMATION REMAINS WITH RECIPIENT. IN NO EVENT SHALL COMPAQ BE LIABLE FOR
ANY DIRECT, CONSEQUENTIAL, INCIDENTAL, SPECIAL, PUNITIVE OR OTHER DAMAGES
WHATSOEVER (INCLUDING WITHOUT LIMITATION, DAMAGES FOR LOSS OF BUSINESS
PROFITS, BUSINESS INTERRUPTION OR LOSS OF BUSINESS INFORMATION), EVEN IF
COMPAQ HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

The limited warranties for Compaq products are exclusively set forth in the documentation accompanying
such products. Nothing herein should be construed as constituting a further or additional warranty.

This publication does not constitute an endorsement of the product or products that were tested. The
configuration or configurations tested or described may or may not be the only available solution. This test
is not a determination or product quality or correctness, nor does it ensure compliance with any federal,
state, or local requirements.

Product names mentioned herein may be trademarks and/or registered trademarks of their respective
companies.

Compaq, Contura, Deskpro, Fastart, Compaq Insight Manager, LTE, PageMarq, Systempro, Systempro/LT,
ProLiant, TwinTray, ROMPaq, LicensePaq, QVision, SLT, ProLinea, SmartStart, NetFlex, DirectPlus,
QuickFind, RemotePaq, BackPaq, TechPaq, SpeedPaq, QuickBack, PaqFax, Presario, SilentCool,
CompaqCare (design), Aero, SmartStation, MiniStation, and PaqRap are registered with the United States
Patent and Trademark Office.

Netelligent, Armada, Cruiser, Concerto, QuickChoice, ProSignia, Systempro/XL, Net1, LTE Elite,
Vocalyst, PageMate, SoftPaq, FirstPaq, SolutionPaq, EasyPoint, EZ Help, MaxLight, MultiLock,
QuickBlank, QuickLock, UltraView, Innovate logo, Wonder Tools logo in black/white and color, and
Compaq PC Card Solution logo are trademarks and/or service marks of Compaq Computer Corporation.

Microsoft, Windows, Windows NT, Windows NT Server and Workstation, and Microsoft SQL Server for
Windows NT are trademarks and/or registered trademarks of Microsoft Corporation.

NetWare and Novell are registered trademarks and intraNetWare, NDS, and Novell Directory Services are
trademarks of Novell, Inc.

Pentium is a registered trademark of Intel Corporation.
Copyright ©1999 Compaq Computer Corporation. All rights reserved. Printed in the U.S.A.
Understanding Compaq StorageWorks RAID Array 4000 and Infrastructure Cabling

White Paper prepared by ECG Technology Communications Group
First Edition (June 1999)

Document Number ECG02030699A

Understanding Compaq StorageWorks RAID Array 4000 and Infrastructure Cabling 3

ECG02030699A

Understanding Fibre Channel Transmission

Note: This paper includes the terms fibre and fiber. Fibre is the international spelling that refers
to the Fibre Channel Standards that include both optical and copper media. Fiber refers to the
optical media used to implement Fibre Channel.

Fibre Channel uses lasers2 to achieve gigabit data transmission rates. The ones and zeros used to
convey information are generated by turning a laser on and off. The receiver detects these bursts
of light and converts them to electrical signals.

Lasers used in Fibre Channel transmit light in two wavelength ranges:

• Shortwave, 770 to 860 nanometers

• Longwave, 1,270 to 1,355 nanometers

Optical fiber cable is the medium used in RA4000 solutions. Characteristics of optical fiber cable
are:

• High bandwidth.

• Transmits data over long distances.

• Increased data transmission reliability.

• Immunity to electrical noise.

• Does not radiate energy.

Optical fiber cable is categorized as either multi-mode3 or single-mode. In Figure 1, the diameter
of a multi-mode fiber is large enough to allow multiple streams of light to travel on different
paths from the transmitter to the receiver. Shortwave lasers are used with multi-mode fiber to
transmit data up to 500 meters.

Figure 1. Multi-mode fiber cable

2

Laser technology uses fiber optic media only.

3

Mode means path.

Understanding Compaq StorageWorks RAID Array 4000 and Infrastructure Cabling 4

ECG02030699A

In Figure 2, the small diameter of a single-mode fiber allows one coherent stream of light to
travel along a single path. Longwave lasers are used with single-mode fiber to transmit data up to
10 kilometers.

Figure 2. Single-mode fiber cable

Understanding Fiber Types

Types of fibre channel media4 include:

• 62.5-micron multi-mode.

• 50-micron multi-mode.

• 9-micron single-mode.

4

The fiber types are distinguishable by their data transmission rates and distance capabilities.

Understanding Compaq StorageWorks RAID Array 4000 and Infrastructure Cabling 5

ECG02030699A

Distance Limitations

Two factors that can limit the distance between the components are:

1. The data transmission rate—as shown in Table 1, the distance between the components of

each fiber type tends to decrease as the data transmission rate increases.

2. The degree of attenuation—attenuation is the reduction of the signal strength during

transmission from point to point. In this case, it is the light passing through the optic media.
The number of connectors and splices used to connect components affects the distance that
can exist between components.

Table 1. Data transmission rates and distance capabilities of fiber types

Transmission Rate

Supported by
Compaq

62.5-micron 50-micron 9-micron

100 MB/s

5

Yes 300 m 500 m 10 km

200 MB/s Future

6

150 m 300 m 2 km

400 MB/s Future 90 m 150 m 2 km

Formulas used to calculate the distance limitations are based on the data transmission rates and
the degree of attenuation. A company that provides fiber products and installation and testing
services can help determine distance capabilities and limitations for a particular installation. See
Acknowledgements and References later in this document.

Connection Components

To build a storage system that uses fibre channel technology, it is necessary to understand the use
and function of, hubs, gigabit interface converters (GBICs), and fibre channel cables and
connectors.

• Hubs allow of different GBIC types to be mixed so there can be different cable types within a

fibre channel topology. Hubs use port bypass circuitry to keep a fibre channel loop topology
intact.

• GBICs convert electrical signals to optical signals and optical signals to electrical signals at

the point where fiber cables connect to copper-wired components (hubs, controller cards, and
host adapters).

• Fibre channel cables and connectors join system components and connect to infrastructure

cabling.

5

Megabytes per second

6

A 200 MB/s transmission rate may be passed over in favor of a 400 MB/s transmission rate.