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N series SnapMirror Async Guide

Book Description

This IBM® Redbooks® publication presents an overview of implementing N series SnapMirror Async technology, with step-by-step configuration examples and recommendations to assist the reader in designing an optimal SnapMirror solution.

There are several approaches to increasing data availability in the face of hardware, software, or even site failures. Backups provide a way to recover lost data from an archival medium (tape or disk). Redundant hardware technologies also help mitigate the damage caused by hardware issues or failures. Mirroring provides a third mechanism to facilitate data availability and minimize downtime.

SnapMirror offers a fast and flexible enterprise solution for mirroring or replicating data over local area, wide area, and Fibre Channel (FC) networks. SnapMirror can be a key component in implementing enterprise data protection strategies. If a disaster occurs at a source site, businesses can access mission-critical data from a replica on a remote N series storage system for uninterrupted operation.

Table of Contents

  1. Front cover
  2. Notices
    1. Trademarks
  3. Preface
    1. The team who wrote this book
    2. Now you can become a published author, too!
    3. Comments welcome
    4. Stay connected to IBM Redbooks
  4. Chapter 1. Introduction to SnapMirror
    1. 1.1 Business applications
      1. 1.1.1 Disaster recovery
      2. 1.1.2 Remote data access
      3. 1.1.3 Application development, testing, and disaster recovery testing
      4. 1.1.4 Remote tape archiving
      5. 1.1.5 Load sharing
    2. 1.2 Benefits of SnapMirror
    3. 1.3 Summary of SnapMirror changes in Data ONTAP 7.3
      1. 1.3.1 Increased concurrent transfers
      2. 1.3.2 Efficient use of multiprocessor systems
      3. 1.3.3 Efficient computation of changed blocks
  5. Chapter 2. Overview of SnapMirror
    1. 2.1 The basics
    2. 2.2 Control files
      1. 2.2.1 snapmirror.conf
      2. 2.2.2 snapmirror.access
      3. 2.2.3 snapmirror.allow
    3. 2.3 Update process
    4. 2.4 Snapshot copy behavior in SnapMirror
    5. 2.5 Volume SnapMirror and qtree SnapMirror
    6. 2.6 SnapMirror volume replication
      1. 2.6.1 Characteristics of volume SnapMirror
      2. 2.6.2 Snapshot copy behavior and status in volume SnapMirror
    7. 2.7 SnapMirror qtree replication
      1. 2.7.1 Snapshot copy behavior and status in qtree SnapMirror
      2. 2.7.2 Key differences between volume and qtree SnapMirror
    8. 2.8 Support for volume types
    9. 2.9 Modes of SnapMirror
      1. 2.9.1 SnapMirror Async
      2. 2.9.2 SnapMirror Sync
      3. 2.9.3 SnapMirror Semi-Sync
      4. 2.9.4 Visibility interval
    10. 2.10 Configuration files
      1. 2.10.1 Access and security
      2. 2.10.2 Distribution
      3. 2.10.3 Configuration changes
    11. 2.11 Multipath support
      1. 2.11.1 Multiplexing mode
      2. 2.11.2 Failover mode
      3. 2.11.3 SnapMirror network compression
      4. 2.11.4 Network bandwidth versus RPO
      5. 2.11.5 What is SnapMirror network compression
      6. 2.11.6 Prerequisites for SnapMirror network compression
  6. Chapter 3. Operational behaviors
    1. 3.1 Active-Active configuration
    2. 3.2 Disk geometry
    3. 3.3 Cascading
      1. 3.3.1 Example of cascading
      2. 3.3.2 Snapshot copy propagation in a cascade configuration
    4. 3.4 Logging
    5. 3.5 Data ONTAP versions and resync
    6. 3.6 Data change rate
    7. 3.7 SnapMirror and LUNS
    8. 3.8 Space guarantees
      1. 3.8.1 Overcommitting aggregates on the source system
      2. 3.8.2 Overcommitting aggregates on the destination system
    9. 3.9 Update failures
    10. 3.10 Concurrent replication operations
    11. 3.11 NearStore personality
    12. 3.12 System-wide throttle
    13. 3.13 Dynamic throttle
    14. 3.14 Firewall configuration
      1. 3.14.1 SnapMirror Async
      2. 3.14.2 SnapMirror Sync and SnapMirror Semi-Sync
    15. 3.15 Network compression configuration and operation configuration
    16. 3.16 Enabling and disabling network compression
    17. 3.17 Reporting the compression ratio
    18. 3.18 Compression ratio and data sets
    19. 3.19 64-bit aggregates
    20. 3.20 SnapMirror over Fibre Channel
  7. Chapter 4. Guidelines for SnapMirror
    1. 4.1 Growing destination volume
    2. 4.2 SnapMirror window size, network latency, and compression
      1. 4.2.1 Window size changes in Data Ontap 7.3.2
      2. 4.2.2 Volume SnapMirror TCP window size limits
      3. 4.2.3 SnapMirror TCP window size and throughput
      4. 4.2.4 SnapMirror TCP window size and compression
    3. 4.3 Replication network configuration
    4. 4.4 Replication frequency and Snapshot schedules
    5. 4.5 Destination Qtree names
    6. 4.6 Many-to-one configuration
    7. 4.7 Upgrading to flexible volumes
    8. 4.8 Unicode
    9. 4.9 High file count environments and Qtree SnapMirror
    10. 4.10 Read performance on a FlexVol volume SnapMirror destination
    11. 4.11 Data ONTAP upgrade and revert considerations
    12. 4.12 SnapMirror network compression considerations
      1. 4.12.1 Compression versus decompression
      2. 4.12.2 Transfer times
      3. 4.12.3 Compression ratio
  8. Chapter 5. Network-free seeding
    1. 5.1 SnapMirror to tape
      1. 5.1.1 Overview
      2. 5.1.2 Restrictions
    2. 5.2 Logical Replication (LREP)
      1. 5.2.1 Overview
      2. 5.2.2 Downloading the LREP tool
  9. Chapter 6. SnapMirror management
    1. 6.1 Protection Manager
    2. 6.2 Concepts
    3. 6.3 Data conformance and monitoring
    4. 6.4 Disaster recovery
  10. Chapter 7. Use of SnapMirror with other N series products
    1. 7.1 N series Manageability Suite
      1. 7.1.1 Application Suite and Database Suite
      2. 7.1.2 Server Suite
    2. 7.2 FlexClone
      1. 7.2.1 Volume SnapMirror, SnapDrive, and FlexClone
      2. 7.2.2 Qtree SnapMirror and FlexClone
      3. 7.2.3 Splitting and destroying a clone
      4. 7.2.4 Invalid operations
    3. 7.3 Setting up replication between FlexClone volumes
    4. 7.4 SnapVault
      1. 7.4.1 Differences between SnapMirror and SnapVault
      2. 7.4.2 Two types of SnapVault deployments with SnapMirror
    5. 7.5 SnapLock
      1. 7.5.1 Replication restrictions
      2. 7.5.2 End-to-end Snaplock Compliance
      3. 7.5.3 Synchronous replication
    6. 7.6 MultiStore
      1. 7.6.1 Virtual storage controller DR
      2. 7.6.2 Virtual storage controller migration
    7. 7.7 MetroCluster
    8. 7.8 FlexShare
    9. 7.9 Deduplication for N series
      1. 7.9.1 Volume SnapMirror
      2. 7.9.2 Qtree SnapMirror
      3. 7.9.3 Data ONTAP 7.3 and volume SnapMirror
      4. 7.9.4 Failback
      5. 7.9.5 Migration
  11. Chapter 8. Tips for troubleshooting
  12. Chapter 9. Examples
    1. 9.1 Failover and failback with SnapMirror
      1. 9.1.1 Planned failover (no disaster)
    2. 9.2 Failover in the event of a real disaster
      1. 9.2.1 Failover
      2. 9.2.2 Replicating to the primary site
      3. 9.2.3 Performing failback to the primary site
      4. 9.2.4 Replicating to the DR site
      5. 9.2.5 Housekeeping
    3. 9.3 SnapLock and qtree SnapMirror resync
      1. 9.3.1 Production failure
      2. 9.3.2 DR testing
    4. 9.4 Making the SnapVault destination writable
    5. 9.5 Migrating SnapVault by using SnapMirror
  13. Related publications
    1. IBM Redbooks
    2. Other publications
    3. Online resources
    4. Help from IBM
  14. Back cover