Front cover SVC V4.2.1 Advanced Copy Services New Advanced Copy Services functionality Server integration examples Scripting examples Jon Tate Pall Thorir Beck Tom Jahn Dan Rumney ibm.com/redbooks International Technical Support Organization SVC V4.2.1 Advanced Copy Services May 2008 SG24-7574-00 Note: Before using this information and the product it supports, read the information in “Notices” on page ix. First Edition (May 2008) This edition applies to the IBM System Storage SAN Volume Controller V4.2.1. © Copyright International Business Machines Corporation 2008. All rights reserved. Note to U.S. Government Users Restricted Rights -- Use, duplication or disclosure restricted by GSA ADP Schedule Contract with IBM Corp. Contents Notices . ix Trademarks . .x Preface . xi The team that wrote this book . xi Become a published author . xiii Comments welcome. xiii Chapter 1. Introduction to SVC V4.2.1 Advanced Copy Services. 1 1.1 New in FlashCopy . 2 1.1.1 Incremental FlashCopy . 2 1.1.2 Cascaded FlashCopy . 2 1.1.3 Dynamically configurable replication services space . 2 1.1.4 Grain size . 2 1.1.5 Bitmap space . 3 1.1.6 Cleaning mode . 3 1.2 New in Remote Copy . 3 1.3 Other new functionality in V4.2.1 . 3 1.3.1 Increased storage addressing. 3 1.3.2 Volume management . 4 1.3.3 Testing managed disks before adding to MDisk groups . 4 1.3.4 Cache . 4 Chapter 2. Planning for Advanced Copy Services implementation . 5 2.1 First questions. 6 2.2 Reasons for copying data . 6 2.3 Deciding what data to copy . 7 2.4 Ensuring usable copied data sets . 7 2.4.1 Understanding caching . 8 2.4.2 Understanding consistency. 12 2.5 Accessing the copied data set . 16 2.6 Determining how much data can be replicated . 16 2.6.1 VDisk capacity limit . 17 2.7 Understanding your current environment . 18 2.7.1 Storage controller information. 19 2.7.2 Server information. 20 2.7.3 Rate of transfer of data . 20 2.7.4 Intersite latency. 21 2.8 Administration of copy services. 21 2.8.1 SSH keys . 21 2.8.2 Command auditing . 21 2.8.3 Authorization roles . 21 2.9 Removing workarounds with V4.2.1 new functions. 22 Chapter 3. Remote Copy: Metro Mirror and Global Mirror . 25 3.1 Remote Copy services overview. 26 3.1.1 Metro Mirror . 26 3.1.2 Cluster partnership . 27 3.1.3 Intercluster communication . 28 © Copyright IBM Corp. 2008. All rights reserved. iii 3.1.4 Maintenance of the intercluster link. 28 3.1.5 I/O channel . 29 3.1.6 Background copy . 29 3.1.7 Remote Mirror relationship . 30 3.1.8 Copy relationship naming convention . 31 3.1.9 Supported methods for synchronizing. 32 3.1.10 Remote Mirror consistency groups . 33 3.2 State overview. 34 3.2.1 Connected or disconnected . 34 3.2.2 Consistent or inconsistent. 35 3.2.3 Consistent or synchronized. 36 3.2.4 Copy states . 36 3.3 Metro Mirror and Global Mirror configuration limits . 40 3.4 Remote Copy internals . 40 3.4.1 Read stability . 40 3.4.2 Write ordering . 41 3.4.3 Write consistency . 41 3.4.4 Write completion . 42 3.4.5 Freeze/Run on consistency groups. 42 3.4.6 Management of difference map . 43 3.4.7 Non-volatile journal . 44 3.4.8 Quick Recovery Copy and Reconstruct . 45 Chapter 4. Implementing Remote Copy . 47 4.1 Implementation . 48 4.2 Implementation using the GUI. 49 4.2.1 Creating a cluster partnership. ..