Gateway 840 VT-100 User Manual

Gateway 840 VT-100

User's Guide

Installing

Getting Help

1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Troubleshooting assistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2 Accessing the Configuration Utility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Accessing the utility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Using the VT-100 terminal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Navigating the SATA RAID configuration utility . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Menu system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Viewing controller information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

3 Creating Disk Arrays. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Understanding arrays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Optimization and drive selection for RAID 5 arrays . . . . . . . . . . . . . . . . . . . . . 21

Creating arrays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Configuring array read-ahead and writeback cache . . . . . . . . . . . . . . . . . . . . . . . . 36

Read-ahead cache . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Writeback cache . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Assigning hot spare drives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Deleting an array . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Expanding an array . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Adding additional drives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Adding additional sub-arrays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Trusting an array . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

4 Logical Drives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

Accessing the LUN configuration menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Viewing unassigned free space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

Creating a logical drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Expanding a logical drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

Setting logical drive availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

Deleteing a logical drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

Modifying a mapped LUN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

5 SAN LUN Mapping

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .90

Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

Accessing the SAN LUN mapping configuration menu . . . . . . . . . . . . . . . . . . . . . .91

Viewing SAN LUN mappings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .93

Creating a SAN LUN mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .96

Deleting a SAN LUN mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .100

Modifying SAN LUN Mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .103

Viewing connected hosts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .108

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .89

6 Advanced Configuration and Management . . . . . . . . . . . . . . . . . . . . .111

Setting rebuild parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .112

Enabling/disabling auto rebuild . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .112

Configuring auto hot spare . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .115

Configuring hot spares . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .118

Viewing the list of hot spare drives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .118

Adding or removing hot spare drives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .121

Configuring the hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .124

Setting the controller LUN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

Setting the controller port ID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .127

Controller port data rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .130

Setting the RS-232 configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .133

Packetized data transfers/QAS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .136

Viewing controller information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .138

Clearing the configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .140

7 Additional Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .143

Modifying the configuration name . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .144

Verifying background media . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .147

Including enclosure events in event logs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .150

8 Statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .153

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .154

Viewing all statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .155

Dumping data to a text file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .157

Viewing access statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .158

Viewing readahead statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .161

Viewing command cluster statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .163

Viewing miscellaneous statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .165

Viewing access statistics on each logical drive . . . . . . . . . . . . . . . . . . . . . . . . . . . 166

Clearing access statistics on each logical drive (LUN) . . . . . . . . . . . . . . . . . . . . .170

Clearing all statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .170

9 Event Logs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173

Accessing event logs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174

Controller events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178

Drive events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184

Controller drive port (host) events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190

Enclosure events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192

Failed drives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195

Clearing event logs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196

10 Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199

Accessing diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200

Using offline diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202

Using online diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205

Controller maintenance - downloading firmware . . . . . . . . . . . . . . . . . . . . . . . . . 207

Drive maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211

Download the firmware from the host . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212

Checking RAID 5/50 parity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217

Tracing commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220

Shutting down the controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223

Dumping diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225

11 Optimizing RAID 5 Write Performance . . . . . . . . . . . . . . . . . . . . . . . . . 227

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228

Sequential access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229

Number of outstanding commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229

Access size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229

Access alignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229

Using RAID 5 sub-arrays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230

Experiencing multiple drive failures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231

Promoting faster rebuild . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232

A Technical Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233

Technical Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234

Telephone numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234

Notices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237

iii

Introduction

This guide provides the operational and reference information to configure and manage the RAID controllers installed in your Gateway 840 Series storage system. The controllers are accessed through a VT-100 terminal using a menu-based user interface, connected directly to the RAID controllers.

This guide contains step-by-step procedures to access the VT-100 terminal utility, as well as perform configuration functions and enclosure monitoring.

Chapter 1: Introduction

Features

Your Gateway 840 has a menu-based software utility designed to configure and manage the RAID controller in your new storage enclosure. It provides centralized management to control primary storage assets vital to ensuring maximum data reliability, network up-time, and system serviceability. It lets you manage the storage system by accessing the configuration utility locally.

This software guide provides the operational and reference information to configure and manage the SATA RAID controller installed in your Gateway 840, using this menu-based user interface.

The following are some of the major features of local RAID configuration utility.

■ Simple, straight-forward user interface

■ Menu-based interface that works with a wide range of operating systems

■ Easy access and navigation

■ Host LUN and LUN mapping configuration

■ A comprehensive, non-volatile event log

■ Useful offline or online diagnostics

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Troubleshooting assistance

To help troubleshoot problems with your system, the Event Logs chapter, as well as on-line help, provides a list of all the events that can occur, along with a suggested cause and action to take. When a warning or error event occurs, you can review the event log, locate the suspect event, and see “Event Logs”

on page 173 or help section to determine the possible cause or causes and the

suggested action to take. Also see “Diagnostics” on page 199.

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Chapter 1: Introduction

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Accessing the

Configuration

Utility

This chapter provides information on accessing the configuration utility. Read this chapter to learn how to:

■ Access the utility

■ Use the VT-100 terminal

■ Navigate the configuration utility

■ View controller information

Chapter 2: Accessing the Configuration Utility

Accessing the utility

You can access the SATA RAID controller by using a VT-100 terminal connected to the RS-232 serial ports on the controller’s rear panel. Configure your terminal using the procedures described in “Using the VT-100 terminal” on page 7.

Important You can also choose to use StorView Storage

Management software to manage and monitor the enclosure and SATA RAID Controller. Refer to the

840 SATA RAID StorView User’s Guide

information.

Gateway

for more

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Using the VT-100 terminal

Access to the RAID controller is accomplished by using its onboard configuration utility with a VT-100 terminal or terminal emulation connected to the RS-232 serial port on the controller.

A SATA communication RS-232 cable (provided with the hardware) is used to connect the terminal to the serial port on the SATA RAID controller.

Configure your host system or terminal RS-232 port to use the following settings:

Setting Value

Terminal Emulation ANSI

Function Terminal Keys

Fonts Terminal

Translations None

Columns 80

Set the communications parameters for the terminal program as follows:

Setting Value

Baud Rate 115,200

Data Bits 8

Stop Bits 1

Parity None

Flow Control None

Connector COM1 (typically)

To access the RAID controllers:

1 Connect the host terminal to the serial port on the controller using a

null-modem serial cable (use the configuration information in the preceding tables).

2 Turn on the terminal and the Gateway 840 Series storage system.

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Chapter 2: Accessing the Configuration Utility

3 From the computer or terminal connected to the RAID controller, start your

terminal emulation software.

Important Make sure that your terminal emulation software is set to

use the correct COM port on your computer.

4 From the terminal window, press CTRL + W. The Main Menu opens.

You can now perform all of the functions described in the following chapters. All steps begin from the Main Menu.

If an event or error occurs, you can review the log for the problem by examining the event log (see “Event Logs” on page 173).

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Navigating the SATA RAID configuration utility

The SATA RAID keys on your keyboard. The table below describes the primary navigation and selection methods.

To Do this

Toggle interface from text-base to menu-based.

Return to the previous menu or screen (Exit).

Move the selection. Press the arrow keys.

Select a menu option. Press the ENTER key.

configuration utility

Press CTRL + W keys.

Press the

menu system can be navigated using the

ESC key.

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Chapter 2: Accessing the Configuration Utility

Menu system

Configuration Menu

View Configuration Array Configuration LUN Configuration Hot Spare Configuration Rebuild Parameters

840 SATA RAID Configuration Utility

Main Menu

Configuration Menu Controller Information Statistics Event Logs Diagnostics Enclosure Information

UPS Configuration Hardware Configuration Clear Configuration Additional Configuration

Controller Information

View Controller

Displays controller information.

Array Configuration

View Array Create Array Delete Array Expand Array Array Cache Configuration View Unused Drives Advanced Array Configuration

LUN Configuration

LUN Management SAN LUN Mapping

Hot Spare Configuration

View Hot Spare Drive Configuration Add or Remove Pool and Dedicated Spare

Statistics

View Controller

Event Logs

View Controller

Diagnostic

Offline Diagnostics Online Diagnostics Reset Controller Shutdown Controller Diagnostics Dump

Rebuild Parameters

Auto Rebuild and Set Priority Auto Hot Spare

Hardware Configuration

Controller LUN Port ID Settings Controller Port Data Rate RS232 Settings Packetized SCSI/QAS

Clears All Configurations

Additional Configuration

Modify Configuration Name Modify Configuration WWN Backgroun Verification Log Enclosure Events

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Menu system (continued)

Array Configuration Menu

View Array Create Array Delete Array Expand Array Array Cache Configuration View Unused Drives Advanced Array Configuration

Navigating the SATA RAID configuration utility

Displays Array Information

Create Array

Select an Array Delete the Array

Select an Array Add Drives to the Array Add Sub-Arrays to Current Array

Read-Ahead Cache Writeback Cache

Displays the Unused Drives

Initialize Array Trust Array

Steps through the create array process.

LUN Configuration Menu

LUN Management SAN LUN Mapping

Hot Spare Configuration Menu

View Hot Spare Drive Configuration

Add or Remove Pool and Dedicated Spare

Rebuild Parameters Menu

Auto Rebuild and Set Priority

Auto Hot Spare

Hardware Configuration Menu

Controller LUN Port ID Settings Controller Port Data Rate RS232 Settings Packetized SCSI/QAS

Displays Spare Drives

Select Drive Add/Remove

Auto Rebuild: Disabled Rebuild Priority: 50%

Auto Hot Spare: Disabled

Controller LUN Number: 000 Current

Port ID Selection

RS232 Setting

Packetized SCSI/QAS

Enable/Disable

115200 57600 38400 19200 9600

LUN Management

View Logical Drive Create Logical Drive Expand Logical Drive Set Availability Delete Logical Drive View Unassigned Free Space Modify Mapped LUN Number

SAN LUN Mapping

View SAN LUN Mappings Create SAN LUN Mapping Delete SAN LUN Mapping Modify SAN LUN Mapping View Connected Hosts

Controller Port 0 Hard Address: 04 Controller Port 1 Hard Address: 05

Set Controller Port 0 Data Rate Set Controller Port 1 Data Rate

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Chapter 2: Accessing the Configuration Utility

Menu system (continued)

Controller Information

View Controller

Displays Controller Parameters

Statistics

View Controller

View All Statistics View Access Statistics View Readahead Statistics View Command Clustering Statistics

Event Logs

View Controller

View Miscellaneous Statistics Clear Statistics View Access Statistics On Each Logical Drive Clear Access Statistics On Each Logical Drive

View All Events View New Events View Last 50 Events View Last Hour Events View Last 24 Hours Events View Drive Port Events View Controller Port Events View Environment Events View Failed Drive List Clear Event Log

Select Logical Drive

View Access Statistics on Port 0 View Access Statistics on Port 1 View Access Statistics on Both Ports

Select Logical Drive

Clear Access Statistics on Port 0 Clear Access Statistics on Port 1 Clear Access Statistics on Both Ports

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Viewing controller information

Detailed information on the RAID controller is available through the Main Menu, and includes:

■ Controller World Wide Name (WWN)

■ Firmware information

■ Run-time information

■ Temperature and voltage information

To view controller information:

1 After the controller(s) have completed booting, press CTRL + E, then press

TRL + W to switch to the menu-based mode. The Main Menu opens.

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Chapter 2: Accessing the Configuration Utility

2 From the Main Menu select Controller Information, then press ENTER. The

Controller Information screen opens.

3 Select the controller you want to examine by using the spacebar to select

the controller, then press E selection is listed.

The following is a brief summary of the information displayed.

Item Description

Controller WWN An 8-byte unique World Wide Name the controller uses

Configuration WWN An 8-byte World Wide Name the controller uses for

Config Name A 64-byte ASCII name used to identify a specific

NTER. If only one controller is present, only one

for identification. This is unique to each controller, and preprogrammed.

identification to hosts. This can be identical to the Controller WWN, or can be different.

controller configuration.

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Viewing controller information

Item Description

Firmware Revision The firmware version in use by the controller.

Firmware Date/Time Date and time of when the firmware was created.

Total Power on Count The number of times this controller has been power

cycled.

Total Power on Time The total length of time this controller has been powered

on.

Current Power on Time The length of time since this controller has last been

powered on or reset.

Current Controller Time This is the current time on the controller.

Last Configuration Time This is the time the controller was last configured.

Onboard Temperature This is the current temperature as measured by the

controller. If this value exceeds predefined limits, an event will be written into the event log.

Controller Voltage Current readings for various controller and coprocessor

(if applicable) voltages.

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Chapter 2: Accessing the Configuration Utility

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Creating Disk

Arrays

This chapter provides information on creating disk arrays. Read this chapter to learn how to:

■ Understand arrays

■ Create arrays

■ Configure array read-ahead and writeback cache

■ Assign hot spare drives

■ Delete an array

■ Expand an array

■ Trust an array

Chapter 3: Creating Disk Arrays

Overview

Configuring a RAID system requires some planning to make sure that you define the correct RAID levels and array options. It may be helpful to refer to the Topology chapter in the Gateway 840 SATA RAID Enclosure User’s Guide.

This chapter will step you through the process to create the disk arrays. You will also find sections on deleting arrays, expanding arrays, and assigning hot spare drives. You are then directed to the next chapter for the procedures to define the logical drives, which makes the drive array(s) available to the operating system.

This manual assumes you have a basic understanding of RAID concepts and terminologies.

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Understanding arrays

You can create an array at any time. The table below describes the drive requirements for each RAID level.

RAID Level Minimum No. of Drives Maximum No. of Drives

0112

1212

5312

50 6 12

10 (Mirrored) 4 12

Important Before you create more than one array, you must be sure

that your host operating system supports multiple Logical Unit Numbers (LUNs). Most operating systems do support multiple LUNs, or have an option for it. If your operating system does not support multiple LUNs, the host will only be able to see one array at the first disk LUN.

Understanding arrays

Terminology

The following describes the terminology used when creating and managing arrays.

Term Description

Array A group of drives that are combined together to create a

single large storage area. Up to 64 arrays are supported, each containing up to 12 drives per array. There is no limit for the drive size in the arrays.

Chunk Size This is the amount of data that is written on a single drive

before the controller moves to the next drive in the stripe.

Stripe Size This is the number of data drives multiplied by the chunk

size.

Cache Flush Array This is the array that is used to automatically flush cache

data in the situation where power has failed to some of the drives.

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Chapter 3: Creating Disk Arrays

Initialization RAID 5/50 arrays must have consistent parity before they

Reserved Capacity In order to allow drives from a different family or

RAID Level 0 RAID 0 is defined as disk striping where data is striped or

can be used to protect data. Initialization writes a known pattern to all drives in the array. If you choose not to initialize an array, this is known as a “trusted array” and any drive failure will result in data corruption. It is possible to later perform a parity rewrite, which recalculates the parity based on the current data, thus ensuring the data and parity are consistent.

manufacturer to be used as a replacement for a drive in an array, we recommend that a small percentage of the drive’s capacity be reserved when creating the array. This is user selectable, from 0 to 10 percent.

spread across one or more drives in parallel. RAID 0 is ideal for environments in which performance (read and write) is more important than fault tolerance or you need the maximum amount of available drive capacity in one volume. Drive parallelism increases throughput because all drives in the stripe set work together on every I/O operation. For greatest efficiency, all drives in the stripe set must be the same capacity. Because all drives are used in every operation, RAID 0 allows for single-threaded I/O only (i.e., one I/O operation at a time). Environments with many small simultaneous transactions (e.g., order entry systems) will not get the best possible throughput.

RAID Level 1 RAID 1 is defined as disk mirroring where one drive is an

exact copy of the other. RAID 1 is useful for building a fault-tolerant system or data volume, providing excellent availability without sacrificing performance.

RAID Level 5 RAID 5 is defined as disk striping with parity where the

parity data is distributed across with parity all drives in the volume. Normal data and parity data are written to drives in the stripe set in a round-robin algorithm. RAID 5 is multi threaded for both reads and writes because both normal data and parity data are distributed round-robin. This is one reason why RAID 5 offers better overall performance in server applications. Random I/O benefits more from RAID 5 than does sequential I/O, and writes take a performance hit because of the parity calculations. RAID 5 is ideal for database applications.

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Understanding arrays

RAID Level 10 RAID 10 is defined as mirrored stripe sets (also known as

RAID 0+1). You can build RAID 10 either directly through the RAID controller (depending on the controller) or by combining software mirroring and controller striping (called RAID 01).

RAID Level 50 This RAID level is a combination of RAID level 5 and RAID

level 0. Individual smaller RAID 5 arrays are striped, to give a single RAID 50 array. This can increase the performance by allowing the controller to more efficiently cluster commands together. Fault tolerance is also increased, as one drive can fail in each individual array.

Sub-array In RAID 50 applications, this is the name given to the

individual RAID 5 arrays that are striped together. Each sub-array has one parity drive.

Optimization and drive selection for RAID 5 arrays

Typical RAID 5 implementations require a number of steps to write the data to the drives. In order to optimize your system performance based on the type of writes you expect in your operation, we have provided detailed information on optimizing the performance using full strip write operations in an appendix (see “Optimizing RAID 5 Write Performance” on page 227).

If you intend to setup a RAID 5 array and want to consider optimum performance, you will need to consider the number of drives, parity drives, and chunk size. You should review the information provided in “Optimizing RAID

5 Write Performance” on page 227. Additional information is provided at the

appropriate step during configuration.

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Chapter 3: Creating Disk Arrays

Creating arrays

Configuring the arrays involves a few basic steps. All configuration parameters are stored on all hard drives that are members of the specific array. This makes it possible to remove and replace controllers without requiring any configuration changes. The configurations can be viewed or modified through the controller’s RS-232 port.

Important We recommend that you make notes about the arrays you

Important When creating arrays and logical drives, make sure that

create in case you need to duplicate the configuration for an array. See “Trusting an array” on page 61

you are in compliance with the following guidelines:

- Maximum drives per array = 12

- Maximum number of arrays = 64

- Maximum number of logical drives = 512

No changes are made until the configuration is saved, so it is possible to quit at any time without affecting the current configuration as long as you do not save those changes. Configuration can be performed while the system is active.

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Creating arrays

To view an array:

1 From the Main Menu, select Configuration Menu, then press ENTER. The

Configuration Menu opens.

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Chapter 3: Creating Disk Arrays

2 From the Configuration Menu, select View Configuration, then press ENTER.

The View Configuration Screen opens.

The following table provides a description of the fields shown on the screen.

Field Description

No. Drive number in the array.

Vendor ID Indicates the manufacturer of the drive.

Product ID Drive model number.

F/W Drive firmware version.

Ser. No. Drive serial number.

Cap. Drive capacity expressed in GBs.

EN, SL The enclosure and drive slot number, used for drive

identification.

ST The drive status, will either be “OK” or “FL.”

3 Press ESC to return to the previous screen.

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Creating arrays

To create an array:

1 From the Main Menu, select Configuration Menu, then press ENTER. The

Configuration Menu opens.

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+ 220 hidden pages

Gateway 840 VT-100 User Manual

Contents

Introduction

Features

Troubleshooting assistance

Accessing the utility

Using the VT-100 terminal

Navigating the SATA RAID configuration utility

Menu system

Viewing controller information

Overview

Understanding arrays

Terminology

Optimization and drive selection for RAID 5 arrays

Creating arrays