Front cover Achieving the Highest Levels of Parallel Sysplex Availabilitybility The latest availability recommendations Covers hardware, systems management, and software One-stop shopping for availability information Frank Kyne Christian Matthys Uno Bengtsson Andy Clifton Steve Cox Gary Hines Glenn McGeoch Dougie Lawson Geoff Nicholls David Raften ibm.com/redbooks International Technical Support Organization Achieving the Highest Levels of Parallel Sysplex Availability December 2004 SG24-6061-00 Note: Before using this information and the product it supports, read the information in “Notices” on page ix. First Edition (December 2004) This edition applies to IBM Parallel Sysplex technology used with operating systems z/OS (program number 5694-A01) or OS/390 (program number 5647-A01). © Copyright International Business Machines Corporation 2004. 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 redbook. xi Become a published author . xiii Comments welcome. xiv Chapter 1. Introduction. 1 1.1 Why availability is important to you . 2 1.2 Cost of an outage . 2 1.2.1 Component outage versus service outage . 4 1.2.2 Availability overview . 4 1.3 Continuous availability in a Parallel Sysplex . 5 1.3.1 Availability definitions . 5 1.3.2 Spectrum of availability factors . 6 1.4 What this book is all about . 8 Chapter 2. Hardware . 11 2.1 Environmental . 12 2.1.1 Power . 12 2.1.2 Cooling . 13 2.1.3 Geographic location . 13 2.1.4 Physical security . 14 2.1.5 Automation . 14 2.1.6 Physical configuration control . 14 2.2 Central Processing Complexes (CPCs) . 14 2.2.1 How many CPCs to have . 15 2.2.2 Availability features . 15 2.2.3 Concurrent upgrade . 17 2.2.4 Redundant capacity . 21 2.2.5 Hardware configuration. 23 2.3 Coupling Facilities . 24 2.3.1 Coupling Facility Capacity. 25 2.3.2 Failure isolation. 27 2.3.3 Recovering from CF failure . 31 2.3.4 How many CFs . 36 2.3.5 Coupling Facility Control Code Level considerations . 37 2.3.6 CF maintenance procedures. 38 2.3.7 CF volatility . 39 2.3.8 Nondisruptive Coupling Facilities hardware upgrades . 40 2.4 9037 Sysplex Timers considerations . 41 2.4.1 Sysplex Timer® Models . 41 2.4.2 Recovering from loss of all timer signals. 43 2.4.3 Maximizing 9037 availability . 43 2.4.4 Message time ordering . 44 2.5 Intelligent Resource Director. 45 2.5.1 An IRD Illustration . 46 2.5.2 WLM LPAR CPU Management. 47 © Copyright IBM Corp. 2004. All rights reserved. iii 2.5.3 Dynamic Channel-path Management (DCM) . 48 2.5.4 Channel Subsystem I/O Priority Queueing . 50 2.6 Switches . 51 2.6.1 ESCON Directors . 51 2.6.2 FICON Switches . 53 2.7 DASD . 55 2.7.1 Peer to Peer Remote Copy (PPRC) . 57 2.7.2 Extended Remote Copy (XRC). 57 2.8 Geographically Dispersed Parallel Sysplex™. 58 2.8.1 Data consistency. 59 2.8.2 The HyperSwap . 59 2.9 Other hardware equipment . 60 2.9.1 3494 Tape library/VTS . 60 2.9.2 Stand-alone tape. 63 2.9.3 3174, 2074 . 63 Chapter 3. z/OS . 65 3.1 Configure software for high availability . 66 3.1.1 Couple Data Sets . 66 3.1.2 Other important data sets . 71 3.1.3 Sysres and master catalog sharing. 75 3.2 Consoles . 76 3.2.1 Addressing WTO and WTOR buffer shortages. 77 3.2.2 EMCS consoles . ..