Document revision date: 30 March 2001

Contents

Preface
Preface	Preface
Chapter 1
1	Introduction to Volume Shadowing for OpenVMS
1.1	Overview
1.2	Volume Shadowing Tasks and Operations
1.3	Hardware Environment
1.3.1	Memory Requirements
1.3.2	Supported Devices
1.4	Supported Configurations
1.4.1	Maximum Number of Shadow Sets
1.4.2	Shadowing System Disks
1.4.2.1	Obtaining Dump Files of Shadowed System Disk When Minicopy Is Used
1.4.3	Using Minicopy in a Mixed-Version OpenVMS Cluster System
1.4.4	Using Minicopy in a Mixed-Architecture OpenVMS Cluster System
1.4.5	Shadow Sets, Bound Volume Sets, and Stripe Sets
1.5	Shadowing Disks Across an OpenVMS Cluster System
1.6	Installation
Chapter 2
2	Configuring Your System for High Data Availability
2.1	Repair and Recovery from Failures
2.2	Shadow Set Configurations
Chapter 3
3	Preparing to Use Volume Shadowing
3.1	Licensing Volume Shadowing for OpenVMS
3.2	Volume Shadowing Parameters
3.2.1	Guidelines for Using Volume Shadowing Parameters
3.3	Write Bitmap System Parameters
3.3.1	Setting System Parameters
3.3.2	Displaying System Parameters
3.4	Booting from a System Disk Shadow Set
3.5	Booting Satellite Nodes from an MSCP Served System Disk Shadow Set
3.6	Creating and Managing Shadow Sets
Chapter 4
4	Creating and Managing Shadow Sets Using DCL Commands
4.1	Allocating Devices
4.2	Creating a Shadow Set
4.3	Using INITIALIZE/SHADOW/ERASE to Streamline the Formation of a Shadow Set
4.4	MOUNT Command Qualifiers for Shadowing
4.4.1	MOUNT Command Qualifiers Specific to Shadowing
4.4.2	Additional MOUNT Command Qualifiers Used for Shadowing
4.4.3	Creating a Shadow Set With /NOASSIST
4.4.4	Creating a Shadow Set With /SYSTEM and With /CLUSTER
4.5	Adding Shadow Set Members
4.5.1	Adding a Disk to an Existing Shadow Set
4.5.2	Creating a Two-Member Shadow Set and Adding a Third Member
4.5.3	Checking Status of Potential Shadow Set Members With /CONFIRM
4.5.4	Checking Status of Potential Shadow Set Members With /NOCOPY
4.6	Mounting a Shadow Set on Other Nodes in the Cluster
4.6.1	Reconstructing a Shadow Set With /INCLUDE
4.6.2	Mounting a Former Shadow Set Member as a Nonshadowed Disk
4.7	Specifying Disaster-Tolerant Management Attributes (Alpha Only)
4.8	Removing Members and Dissolving Shadow Sets
4.8.1	Removing Members from Shadow Sets
4.8.2	Dissolving Shadow Sets
4.8.3	Dismounting and Remounting With One Less Member for Backup
4.9	Displaying Information About Shadow Sets
4.9.1	Listing Shadow Sets
4.9.2	Listing Shadow Set Members
4.9.3	SHOW DEVICE Examples for Shadow Set Information
4.9.4	Displaying Shadow Set Information With SDA
4.9.4.1	Using SDA to Obtain Information About Third-Party SCSI Devices
4.9.5	Obtaining Shadow Set Information With F$GETDVI
Chapter 5
5	Creating and Managing Shadow Sets with System Services
5.1	Using $MOUNT to Create and Mount Shadow Sets
5.2	$MOUNT Shadow Set Item Codes
5.3	Using $MOUNT to Mount Volume Sets
5.4	Using $DISMOU to Dismount Shadow Sets
5.4.1	Removing Members from Shadow Sets
5.4.2	Dismounting and Dissolving Shadow Sets
5.4.3	Setting $DISMOU Flags for Shadow Set Operations
5.5	Evaluating Condition Values Returned by $DISMOU and $MOUNT
5.6	Using $GETDVI to Obtain Information About Shadow Sets
5.6.1	$GETDVI Shadow Set Item Codes
5.6.2	Obtaining the Device Names of Shadow Set Members
5.6.2.1	Virtual Unit Names
5.6.2.2	Shadow Set Member Names
Chapter 6
6	Ensuring Shadow Set Consistency
6.1	Shadow Set Consistency
6.2	Copy Operations
6.2.1	Unassisted Copy Operations
6.2.2	Assisted Copy Operations
6.3	Merge Operations
6.3.1	Unassisted Merge Operations
6.3.2	Assisted Merge Operations
6.4	Controlling HSC Assisted Copy and Minimerge Operations
6.5	What Happens to a Shadow Set When a System Fails?
6.6	Examples of Copy and Merge Operations
Chapter 7
7	Using Minicopy for Backing Up Data (Alpha)
7.1	What Is Minicopy?
7.2	Different Uses for Copy and Minicopy
7.3	Why Use Minicopy?
7.4	Procedure for Using Minicopy
7.5	Minicopy Restrictions
7.6	Creating Write Bitmaps
7.6.1	Creating a Write Bitmap With DISMOUNT
7.6.2	Creating a Write Bitmap With MOUNT
7.7	Starting a Minicopy Operation
7.8	Master and Local Write Bitmaps
7.9	System Parameters for Managing Write Bitmap Messages and Shadow Set Limit
7.10	Managing Write Bitmaps With DCL Commands
7.10.1	Determining Write Bitmap Support and Activity
7.10.2	Displaying Write Bitmap IDs
7.10.3	Displaying Write Bitmap Status of Cluster Members
7.10.4	Deleting Write Bitmaps
7.11	Performance Implications of Write Bitmaps
7.12	Guidelines for Using a Shadow Set Member for Backup
7.12.1	Removing a Shadow Set Member for Backup
7.12.2	Data Consistency Requirements
7.12.3	Application Activity
7.12.4	RMS Considerations
7.12.4.1	Caching and Deferred Writes
7.12.4.2	End of File
7.12.4.3	Index Updates
7.12.4.4	Run-Time Libraries
7.12.4.5	$FLUSH
7.12.4.6	Journaling and Transactions
7.12.5	Mapped Files
7.12.6	Database Systems
7.12.7	Base File System
7.12.8	$QIO File Access and VIOC
7.12.9	Multiple Shadow Sets
7.12.10	Host-Based RAID
7.12.11	OpenVMS Cluster Operation
7.12.12	Testing
7.12.13	Restoring Data
7.12.14	Revalidation of Data Consistency Methods

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