HP Volume Shadowing for OpenVMS: OpenVMS Version 8.4

HP Part Number: BA554-90020

Published: June 2010

Table of Contents

Intended Audience
Document Structure
Related Documents
Readers Comments
How to Order Additional Documentation
Typographic Conventions
1 Introduction to HP Volume Shadowing for OpenVMS
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
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
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
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
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