Hitachi MK-97DF8018-00 Troubleshooting

Troubleshooting 8–1

Hitachi Simple Modular Storage Copy-on-Write SnapShot User’s Guide

Troubleshooting

Two types of problem can be experienced with a SnapShot

system: pair failure and data pool capacity exceeded. This

chapter discusses the causes and provides solutions for these

problems.

Pair Failure

Data Pool Capacity Exceeded

Contents

Main MK-97DF8018-00 Hitachi Simple Modular Storage Copy-on- Write SnapShot Users Guide ii Preface iv Document Revision Level Safety and Warnings Intended Audience Product Version Release Notes Document Organization Referenced Documents vi Document Conventions Convention for Storage Capacity Values Getting Help Support Contact Information Comments Page Table of Contents 1 SnapShot Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 2 Planning and Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1 4 Enabling and Disabling SnapShot. . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1 5 Configuring SnapShot. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1 Page Page SnapShot Overview 12 Copy-on-Write SnapShot Software Hardware and Software Configuration Figure 1-1: SnapShot functional components How SnapShot Works 14 Volume PairsP-VOLs and V-VOLs Page 16 Data Pools Differential Management LUs (DM-LU) Consistency Group (CTG) SnapShot InterfaceStorage Navigator Modular 2 Planning and Design 22 The Plan and Design Workflow Assessing Business Needs Establishing How Often a Copy Is Made (Copy Frequency) Selecting a Reasonable Time Between Snapshots Establishing How Long a Copy Is Held (Copy Lifespan) Lifespan Based on Backup Requirements 24 Lifespan Based on Business Uses Figure 2-1: V-VOL Frequency, Lifespan Establishing the Number of V-VOLs that Are Required Establishing Data Pool Size Figure 2-2: Write workload and data pool size Measuring Workload Data 26 Figure 2-3: Raw Data Example in MB/sec Figure 2-4: Rolling Averages Calculated Using V-VOL Frequency Figure 2-5: Rolling Averages Graphed Over Raw Averages 28 Rule of Thumb Calculation Table 2-1: Workload Rates when No Measurement Data Pool Key Points Calculating Maximum Capacity 210 Operating System Considerations Identifying P-VOL and V-VOL Cluster Software, Path Switching Software Microsoft Cluster Server (MSCS) Veritas Volume Manager (VxVM) Windows 2000 Windows Server 2003 Linux and LVM Configuration Windows Server 2003/Windows 2000 and Dynamic Disk Page Page Requirements 32 System Requirements Supported Platforms Table 3-2 shows the supported platforms and operating system versions required for SnapShot. Table 3-1: Storage S Minimum Requirements Page 42 Enabling/Disabling SnapShot Page Page Configuring SnapShot 52 Configuration Workflow Assign Volumes for the Data Pool Notes on Adding a Data Pool Set Up the Virtual Volume (V-VOL) (manual method) Page Using SnapShot 62 SnapShot Replication Workflow Back Up Your VolumeCreate a Pair Using the Backup Wizard Create Pair Procedure 64 Update the V-VOL Restore the P-VOL from the V-VOL Restore from Tape 66 Use the V-VOL for Tape Backup, Testing, Reports, Etc. Edit Pairs, Data Pool Delete Pairs, V-VOLs, Data Pools 68 Test the Configuration Monitoring and Maintenance 72 Monitoring SnapShot Monitoring Pair Status Table 7-1: Pair Statuses Monitoring Data Pool Usage Expanding the Data Pool Other Methods for Lowering Data Pool Load Page Troubleshooting 82 Pair Failure Recovering from Pair Failure Due to POOL FULL Recovering from Pair Failure Due to a Hardware Failure Page Page A Operations Using CLI A2 Enabling and Disabling SnapShot Operations for SnapShot Configuration Setting the POOL A4 Setting the V-VOL Performing SnapShot CLI Operations Creating SnapShot Pairs A6 Updating SnapShot Logical Unit Restoring V-VOL to P-VOL Releasing SnapShot Pairs A8 Changing Pair Information Creating Pairs that Belong to a Group Operations Using CLI A9 Sample Back Up Script for Windows This section provides sample script for backing a volume on Windows. Page Page B2 General Specifications Table B-1 lists external specifications for SnapShot. Table B-1: General Specifications Item Specification Maximum Capacity on page 2-9 Table B-1: General Specifications Item Specification Page Glossary1 Glossary Glossary2 A B C Glossary3 Glossary4 Glossary5 D Glossary6 E F Glossary7 G I Glossary8 L Glossary9 M P Glossary10 Glossary11 R Glossary12 S Glossary13 T V W Glossary14 Index-1 Index A B C D Index-2 O P R S Page MK-97DF8018-00