OpenVMS documentation

HP Part Number: BA554-90020

Published: June 2010

Legal Notices

Acknowledgments

Table of Contents

Preface

Intended Audience
Document Structure
Related Documents
Readers Comments
How to Order Additional Documentation
Typographic Conventions

1 Introduction to HP Volume Shadowing for OpenVMS

Overview

Volume Shadowing Tasks and Operations

Hardware Environment

Memory Requirements
Supported Devices

Supported Configurations

Maximum Number of Shadow Sets
Support for Six-Member Shadow Sets
Shadowing System Disks
Using Minicopy in a Mixed-Version OpenVMS Cluster System
Shadow Sets, Bound Volume Sets, and Stripe Sets
Shadowing Disks Across an OpenVMS Cluster System
HBMM Configuration Requirements
HBMM Restrictions
HBMM in a Mixed-Version or Mixed-Architecture OpenVMS Cluster System

Installation

2 Configuring Your System for High Data Availability

Levels of High Data Availability Using Volume Shadowing
Repair and Recovery from Failures
Shadow Set Configurations

3 Preparing to Use Volume Shadowing

Configuration Tasks

Licensing Volume Shadowing for OpenVMS

Volume Shadowing Parameters

Guidelines for Using Volume Shadowing Parameters

Bitmap System Parameters

Setting System Parameters
Displaying System Parameters

Dynamic Volume Expansion (Integrity servers and Alpha)

Using the /SIZE Qualifier With the INITIALIZE Command
When to Increase the Expansion Limit on Each Volume

Booting from a System Disk Shadow Set

Booting Satellite Nodes from a Served, System Disk Shadow Set

4 Creating and Managing Shadow Sets Using DCL Commands

Allocating Devices

Creating a Shadow Set

Using INITIALIZE/SHADOW/ERASE to Form a Shadow Set (Integrity servers and Alpha)

Benefits and Side Effects of Using /ERASE
Requirements for Using INITIALIZE/SHADOW
INITIALIZE/SHADOW Examples

MOUNT Command Qualifiers for Shadowing

MOUNT Command Qualifiers Specific to Shadowing
Additional MOUNT Command Qualifiers Used for Shadowing
Creating a Shadow Set With /NOASSIST
Creating a Shadow Set With /SYSTEM and With /CLUSTER

Adding Shadow Set Members

Adding a Disk to an Existing Shadow Set
Creating a Two-Member Shadow Set and Adding a Third Member
Checking Status of Potential Shadow Set Members With /CONFIRM
Checking Status of Potential Shadow Set Members With /NOCOPY

Mounting a Shadow Set on Other Nodes in the Cluster

Reconstructing a Shadow Set With /INCLUDE
Mounting a Former Shadow Set Member as a Non-shadowed Disk

Managing Shadow Sets With SET SHADOW (Integrity servers and Alpha)

How to Use the Multiple-Site SET SHADOW and DISMOUNT Command Qualifiers

Managing Copy and Merge Operations (Integrity servers and Alpha)

Using /DEMAND_MERGE to Start a Merge Operation
SHOW SHADOW Management Functions

Prioritizing Merge and Copy Operations

Default Management of Merge and Copy Operations
Hierarchy of Transient State Operations
Assigning Priorities to Shadow Sets
Displaying Shadow Set Priority Values
Controlling Which Systems Manage Merge and Copy Operations
Managing Merge Operations
Managing Copy Operations
Managing Transient States in Progress

Removing Members and Dissolving Shadow Sets

Removing Members from Shadow Sets
Dissolving Shadow Sets
Dismounting Shadow Sets in Site-Specific Shutdown Procedures
Dismounting and Remounting With One Less Member for Backup

Displaying Information About Shadow Sets

Listing Shadow Sets
Listing Shadow Set Members
SHOW DEVICE Examples for Shadow Set Information
Using ANALYZE/DISK/SHADOW to Examine a Shadow Set
Displaying Shadow Set Information With SDA
Obtaining Shadow Set Information With F$GETDVI

5 Creating and Managing Shadow Sets with System Services

Using $MOUNT to Create and Mount Shadow Sets

$MOUNT Shadow Set Item Codes

MNT$_FLAGS Item Code
MNT$_SHANAM Item Code
MNT$_SHAMEM Item Code
Points to Remember When Constructing a $MOUNT Item List

Using $MOUNT to Mount Volume Sets

Using $DISMOU to Dismount Shadow Sets

Removing Members from Shadow Sets
Dismounting and Dissolving Shadow Sets
Setting $DISMOU Flags for Shadow Set Operations

Evaluating Condition Values Returned by $DISMOU and $MOUNT

Using $GETDVI to Obtain Information About Shadow Sets

$GETDVI Shadow Set Item Codes
Obtaining the Device Names of Shadow Set Members

6 Ensuring Shadow Set Consistency

Shadow Set Consistency

Copy Operations

Unassisted Copy Operations
Assisted Copy Operations (Alpha)

Merge Operations

Unassisted Merge Operations
Assisted Merge Operations (Alpha)

Controlling HSC Assisted Copy and Minimerge Operations

What Happens to a Shadow Set When a System Fails?

Examples of Copy and Merge Operations

7 Using Minicopy for Backing Up Data (Integrity servers and Alpha)

What Is Minicopy?

Different Uses for Copy and Minicopy

Why Use Minicopy?

Procedure for Using Minicopy

Minicopy Restrictions

Write Bitmaps and Dissimilar Device Shadowing Caution

Creating Bitmaps

Creating a Bitmap With DISMOUNT
Creating a Bitmap With MOUNT

Starting a Minicopy Operation

Master and Local Bitmaps

Managing Bitmaps With DCL Commands

Determining Bitmap Support and Activity
Displaying Bitmap IDs
Displaying Bitmap Status of Cluster Members
Deleting Bitmaps

Performance Implications of Bitmaps

Guidelines for Using a Shadow Set Member for Backup

Removing a Shadow Set Member for Backup
Data Consistency Requirements
Application Activity
RMS Considerations
Mapped Files
Database Systems
Base File System
$QIO File Access and VIOC
Multiple Shadow Sets
Host-Based RAID
OpenVMS Cluster Operation
Testing
Restoring Data
Revalidation of Data Consistency Methods

8 Host-Based Minimerge (HBMM)

Overview of Full Merge and Minimerge Operations

Merge Resulting from a System Failure
Merge Resulting from Mount Verification Timeout
Merge Resulting from use of SET SHADOW/DEMAND_MERGE
Comparison of Merge and Minimerge Operations
Fast Minimerge and Minicopy Operations

Overview of HBMM

Bitmaps: Master and Local
HBMM Policies

HBMM Policy Specification Syntax

Rules Governing HBMM Policies

Guidelines for Establishing HBMM Policies

Selecting the Systems to Host Master Bitmaps
Considerations for Setting a Bitmap RESET_THRESHOLD Value
Using Multiple Policies

Configuring and Managing HBMM

How to Define an HBMM Policy
How to Assign an HBMM Policy to a Shadow Set
How to Activate HBMM on a Shadow Set
How to Disable HBMM on a Shadow Set
How to Remove a Policy Assignment from a Shadow Set
How to Change a Policy Assignment of a Shadow Set
How to Delete a Named Policy from the Cluster
How to Apply a Changed DEFAULT Policy
How to Display Policies
How to Display the Merge Status of Shadow Sets
How to Prevent Merge Operations on a System
Considerations for Multiple-Site OpenVMS Cluster Systems

Use of /DEMAND_MERGE When HBMM Is Enabled

Visible Impact of Transient State Events

Automatic Minicopy on Volume Processing

Multiuse Property for Host-Based Minicopies

Multiuse Property and DISMOUNT Keyword

Examples of Multiuse and Dismount

9 Performing System Management Tasks on Shadowed Systems

Upgrading the Operating System on a System Disk Shadow Set

Procedure for Upgrading Your Operating System

Modifying Data on Individual Shadow Set Members

Performing Backup Operations on a Shadow Set

Restrictions on BACKUP Procedures
Using Copy Operations to Create a Backup
Using the OpenVMS Backup Utility
Using BACKUP/IMAGE on a Shadow Set

Crash Dumping to a Shadowed Disk

10 Performance Information for Volume Shadowing

Factors That Affect Performance of a Shadow Set

Performance During Steady State

Performance During Copy and Merge Operations

Improving Performance of Unassisted Merge Operations
Improving Performance for Merge and Copy Operations
Effects on Performance

Guidelines for Managing Shadow Set Performance

Striping (RAID) Implementation

A Messages

Mount Verification Messages
OPCOM Message
Shadow Server Messages
VOLPROC Messages

Glossary

Index

List of Figures

1-1 Virtual Unit
1-2 Elements of a Shadow Set
1-3 Shadow Sets Accessed Through the MSCP Server
2-1 Levels of Availability
2-2 OpenVMS Cluster System With Two FC Switches, Two Dual Controllers and Two Shadow Sets
2-3 OpenVMS Cluster System With Four Systems, Four FC Switches, Four Dual Controllers, and Two Shadow Sets
2-4 Multiple-Site OpenVMS Cluster System With Four Systems, Four FC Switches, Four Controllers, and Two Shadow Sets
3-1 Booting Satellite Nodes
4-1 Multiple-Site OpenVMS Cluster System With FC and LAN Interconnects
7-1 Application Writes to a Shadow Set
7-2 Application Writes to a Bitmap
7-3 Member Returned to the Shadow Set (Virtual Unit)

List of Tables

1-1 Main Volume Shadowing Tasks, Operation Name, and Related Software
2-1 Types of Failures
3-1 Volume Shadowing Parameters
3-2 SHADOWING Parameter Settings
3-3 System Parameter Settings for Multipath Shadow Sets
3-4 Bitmap System Parameters
4-1 MOUNT Command Qualifiers (Shadowing Specific)
4-2 Additional MOUNT Command Qualifiers (Not Shadowing Specific)
4-3 SET SHADOW Command Qualifiers
4-4 ANALYZE/DISK/SHADOW Command Qualifiers
4-5 F$GETDVI Item Codes for Volume Shadowing
5-1 $DISMOU Flag Options
5-2 SYS$GETDVI Item Codes
6-1 Information in the Storage Control Block (SCB)
7-1 Comparison of Minicopy and Full Copy Performance
7-2 Comparison of Minicopy and Hardware-Assist (DCD) Copy Performance
8-1 Visible Impact of Transient State Events
10-1 RAID Levels

List of Examples

3-1 Nodes Not Registered to Use Volume Shadowing
3-2 MODPARAMS.DAT File
3-3 LANCP Database Example of a Satellite Node
3-4 DECnet Database Example of a Satellite Node
4-1 Creating a Shadow Set
4-2 Using the /NOASSIST Qualifier
4-3 Using the /CLUSTER Qualifier
4-4 Creating a Shadow Set and Adding Third Member
4-5 Using the /CONFIRM Qualifier
4-6 Using the /NPCOPY Qualifier
4-7 Reconstructing Shadow Sets With /INCLUDE
4-8 SHOW SHADOW Sample Output
4-9 ANALYZE/DISK/SHADOW Sample Output
4-10 SDA Display of Third-Party SCSI Device
5-1 Item List to Create and Mount a Shadow Set
5-2 Item List to Add a Member to a Shadow Set
5-3 Item List to Create and Mount a Volume Set
5-4 Removing a Member from a Shadow Set
5-5 Dismounting and Dissolving a Shadow Set Locally
5-6 Dismounting and Dissolving a Shadow Set Across the Cluster
6-1 Copy Operation: Creating a New Shadow Set
6-2 Copy Operation: Adding a Member to an Existing Shadow Set
6-3 No Copy Operation: Rebuilding a Shadow Set
6-4 Merge Operation: Rebuilding a Shadow Set
8-1 Using MULTIUSE and DISMOUNT Keywords (I)
8-2 Using MULTIUSE and DISMOUNT Keywords (II)

HP OpenVMS Systems Documentation

HP Volume Shadowing for OpenVMS: OpenVMS Version 8.4