Front cover IBM PowerVM Virtualization Active Memory Sharing Advanced memory virtualization technology Intelligent flow of memory from one partition to another Increased utilization and flexibility of memory usage Allyson Brito Loïc Fura Bartłomiej Grabowski ibm.com/redbooks Redpaper International Technical Support Organization IBM PowerVM Virtualization Active Memory Sharing June 2011 REDP-4470-01 Note: Before using this information and the product it supports, read the information in “Notices” on page vii. Second Edition (June 2011) This edition applies to AIX Version 7.1, IBM i Version 7.1, Novell Suse SLES11 kernel 2.6.32.12-0.7, HMC Version 7 Release 7.2 SP 1, Virtual I/O Server Version 2.2.010 FP 24 SP 1 running on IBM Power Systems with POWER7 processor-based technology. © Copyright International Business Machines Corporation 2011. 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 . vii Trademarks . viii Preface . ix The team who wrote this paper . ix Now you can become a published author, too! . .x Comments welcome. .x Stay connected to IBM Redbooks . xi Chapter 1. Overview . 1 1.1 Requirements . 2 1.2 Dedicated and shared memory . 2 1.3 Shared memory pool. 4 1.4 Paging Virtual I/O Server . 5 1.5 Shared memory partitions . 6 1.5.1 Logical and physical memory . 6 1.5.2 Memory classification . 7 1.6 Usage examples . 9 1.6.1 Logical memory overcommitment . 9 1.6.2 Physical memory overcommit . 12 Chapter 2. Detailed architecture . 13 2.1 Dedicated versus shared memory model . 14 2.1.1 Dedicated memory model . 14 2.1.2 Shared memory model . 15 2.2 Active Memory Sharing technical details . 16 2.3 Active Memory Sharing components . 19 2.3.1 Virtualization Control Point . 20 2.3.2 Shared memory pool. 20 2.3.3 Active Memory Sharing Manager . 21 2.3.4 Paging Virtual I/O Server . 21 2.3.5 Paging devices . 22 2.3.6 Virtual Asynchronous Service Interface . 23 2.3.7 I/O entitled memory. 23 2.4 Active Memory Sharing supporting technologies . 23 2.4.1 Page loaning . 23 2.4.2 Collaborative Memory Manager . 25 2.4.3 Memory affinity . 25 2.4.4 Components specific to IBM i . 26 2.5 Active Memory Sharing supported technologies. 26 2.5.1 Active Memory Expansion. 26 2.5.2 Partition suspend and resume . 29 2.5.3 Live Partition Mobility . 29 2.6 Processor and memory virtualization compared . 31 Chapter 3. Planning for Active Memory Sharing . 33 3.1 Active Memory Sharing prerequisites . 34 3.2 Deployment considerations. 34 3.2.1 Overcommitment. 34 © Copyright IBM Corp. 2011. All rights reserved. iii 3.2.2 Workload selection . 37 3.2.3 Consolidation factors . 38 3.2.4 Paging device planning. 38 3.3 Sizing Active Memory Sharing . 38 3.3.1 Virtual I/O Server resource sizing . 39 3.3.2 Shared memory partition CPU sizing . 40 Chapter 4. Configuring and managing . 41 4.1 Creating the paging devices . 42 4.2 Creating the shared memory pool. 43 4.3 Creating a shared memory partition . 49 4.4 Managing Active Memory Sharing . 51 4.4.1 Paging device assignment . 51 4.4.2 Adding paging devices . 53 4.4.3 Removing paging devices. 53 4.4.4 Changing the size of a paging device . 53 4.4.5 Managing the shared memory pool size . 54 4.4.6 Deleting the shared memory pool . 54 4.4.7 Dynamic LPAR for shared memory partitions. 55 4.4.8 Switching between dedicated and shared memory. 55 4.4.9 Starting and stopping the Virtual I/O Server . 56 4.4.10 Dual VIOS considerations. 56 Chapter 5. Monitoring . 59 5.1 Management Console . 60 5.2 Virtual I/O Server monitoring. 64 5.3 Monitoring AIX. 66 5.3.1 The vmstat command . 66 5.3.2 The lparstat command . ..