Front cover z/OS Intelligent Resource Director WLM LPAR CPU Management Dynamic Channel-path Management Channel Subsystem I/O Priority Queueing Frank Kyne Michael Ferguson Tom Russell Alvaro Salla Ken Trowell ibm.com/redbooks International Technical Support Organization z/OS Intelligent Resource Director August 2001 SG24-5952-00 Take Note! Before using this information and the product it supports, be sure to read the general information in “Special notices” on page 401. First Edition (August 2001) This edition applies to Version 1 Release 1 of z/OS, Program Number 5694-A01. Note: This book is based on a pre-GA version of a product and may not apply when the product becomes generally available. We recommend that you consult the product documentation or follow-on versions of this redbook for more current information. Comments may be addressed to: IBM Corporation, International Technical Support Organization Dept. HYJ Mail Station P099 2455 South Road Poughkeepsie, NY 12601-5400 When you send information to IBM, you grant IBM a non-exclusive right to use or distribute the information in any way it believes appropriate without incurring any obligation to you. © Copyright International Business Machines Corporation 2001. All rights reserved. Note to U.S Government Users – Documentation related to restricted rights – Use, duplication or disclosure is subject to restrictions set forth in GSA ADP Schedule Contract with IBM Corp. Contents Preface . .ix The team that wrote this redbook. .ix Special notice . .xi IBM trademarks . xii Comments welcome. xii Part 1. Introduction to Intelligent Resource Director . 1 Chapter 1. Introduction to Intelligent Resource Director (IRD). 3 1.1 S/390 - A history lesson . 6 1.2 Why Intelligent Resource Director is the next step . 8 Part 2. WLM LPAR CPU Management . 13 Chapter 2. Introduction to WLM LPAR CPU Management. 15 2.1 What WLM LPAR CPU Management is . 16 2.2 Workload Manager advantages . 17 2.3 Workload Manager highlights . 19 2.4 LPAR concepts I . 21 2.5 LPAR concepts II . 22 2.6 Options prior to WLM LPAR CPU Management . 26 2.7 Problems with existing CPU management options . 28 2.8 Prerequisites for WLM CPU Management . 30 2.9 WLM LPAR Weight Management I . 32 2.10 WLM LPAR Weight Management II . 33 2.11 WLM LPAR Weight Management III . 35 2.12 WLM Vary CPU Management. 37 2.13 Value of WLM LPAR CPU Management . 38 2.14 When do you need WLM LPAR CPU Management?. 39 2.15 Relationship to IBM License Manager . 42 2.16 New terminology for WLM LPAR CPU Management. 44 Chapter 3. How WLM LPAR CPU Management works . 47 3.1 Shared logical CPs example. 50 3.2 LPAR dispatching and shared CPs. 52 3.3 Reasons for intercepts . 55 3.4 LPAR event-driven dispatching . 57 3.5 LPAR weights. 59 3.6 LPAR capping . 64 © Copyright IBM Corp. 2001 iii 3.6.1 LPAR capped vs. uncapped . 67 3.7 What drives WLM LPAR CPU Management decisions . 69 3.8 WLM LPAR Weight Management . 72 3.8.1 WLM LPAR Weight Management example. 78 3.9 WLM LPAR Vary CPU Management. 80 3.9.1 WLM LPAR Vary CPU Management concepts . 82 3.9.2 WLM Vary CPU Management logic . 83 3.9.3 Example - Too many logical CPs online . 86 3.9.4 Example - Exact amount of logical CPs online . 88 3.9.5 Example - Too few logical CPs online. 90 3.10 Effect of WLM Weight Management on WLM Vary CPU Management92 3.11 Switching to WLM Compatibility mode . 93 3.12 Use of CF structures . 96 3.13 How to interface to WLM LPAR CPU Management. 99 Chapter 4. Planning for WLM LPAR CPU Management . 101 4.1 Identifying candidate environments . 103 4.2 WLM Policy definitions . 105 4.3 Hardware prerequisites . 107 4.4 Software prerequisites . 110 4.5 Mixed software releases. 112 4.6 WLM mode considerations . 113 4.7 Coupling Facility prerequisites . 115 4.8 Multiple LPAR Cluster/sysplex configurations. 117 4.9 Recovery considerations . 119 4.10 IBM License Manager considerations . 121 Chapter 5. Implementing WLM LPAR CPU Management. 125 5.1 Example configuration . 126 5.2 WLM definitions . 127 5.3 Defining WLM structures . 129 5.4 z/OS definitions . 131 5.5 HMC definitions . 132 5.5.1 HMC Change LPAR Controls panel . 135 5.6 Migrated demonstration configuration. 136 5.7 Summary . 137 Chapter 6. Operating WLM LPAR CPU Management . 139 6.1 Dynamic HMC operations. 141 6.2 z/OS operator commands. 143 6.3 Managing the WLM CF structure . 146 6.4 Automation considerations . 148 6.5 Problem determination . 149 iv z/OS Intelligent Resource Director Chapter 7. Performance and tuning for WLM CPU Management . 153 7.1 WLM LPAR CPU Management considerations . 154 7.2 RMF reports . 156 7.2.1 RMF Monitor I - CPU Activity Report . 157 7.2.2 RMF Monitor I - LPAR Partition Report. 159 7.2.3 RMF Monitor I - LPAR Cluster Report. 161 7.3 Other RMF reports . 163 7.4 SMF considerations . 164 7.5 A tuning methodology for WLM LPAR CPU Management . 165 Part 3. Dynamic Channel-path Management . 167 Chapter 8. Introduction to Dynamic Channel-path Management . 169 8.1 Supported environments . 170 8.2 Value of Dynamic Channel-path Management . 172 8.2.1 Improved overall I/O performance. 173 8.2.2 Simplified configuration definition . 175 8.2.3 Reduced skills requirement. 177 8.2.4 Maximize utilization of installed resources . 178 8.2.5 Enhanced DASD subsystem availability . 179 8.2.6 Reduced requirement for more than 256 channels. 181 8.3 Devices and channels that can be managed . 182 8.4 New terminology for DCM . 183 8.5 WLM role in Dynamic Channel-path Management . 185 8.6 Environments most likely to benefit . 187 Chapter 9. How Dynamic Channel-path Management works . 189 9.1 Understanding the basics . 190 9.1.1 Life of an I/O . 191 9.1.2 Unit Control Block . 193 9.1.3 Channel subsystem logic . ..