Book Image

vSphere High Performance Cookbook - Second Edition - Second Edition

By : Kevin Elder, Christopher Kusek, Prasenjit Sarkar
Book Image

vSphere High Performance Cookbook - Second Edition - Second Edition

By: Kevin Elder, Christopher Kusek, Prasenjit Sarkar

Overview of this book

vSphere is a mission-critical piece of software for many businesses. It is a complex tool, and incorrect design and deployment can create performance related issues that can negatively affect the business. This book is focused on solving these problems as well as providing best practices and performance-enhancing techniques. This edition is fully updated to include all the new features in version 6.5 as well as the latest tools and techniques to keep vSphere performing at its best. This book starts with interesting recipes, such as the interaction of vSphere 6.5 components with physical layers such as CPU, memory, and networking. Then we focus on DRS, resource control design, and vSphere cluster design. Next, you’ll learn about storage performance design and how it works with VMware vSphere 6.5. Moving on, you will learn about the two types of vCenter installation and the benefits of each. Lastly, the book covers performance tools that help you get the most out of your vSphere installation. By the end of this book, you will be able to identify, diagnose, and troubleshoot operational faults and critical performance issues in vSphere 6.5.
Table of Contents (17 chapters)
Title Page
Credits
About the Authors
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Virtual memory reclamation techniques


VMs perform memory allocation in the same way an operating system handles memory allocation and deallocation. The guest operating system frees a piece of physical memory by adding memory page numbers to the guest free list.

The guest operating system's free list is not accessible to the hypervisor; thus, it is difficult for the hypervisor to know when to free the host physical memory and when the guest physical memory needs to be freed. The hypervisor is completely unaware of which pages are free or allocated to the guest operating system, and because of this, it cannot reclaim the host physical memory when the guest operating system frees guest physical memory.

So the VMware hypervisor relies on memory reclamation techniques to reclaim the host physical memory that is freed by the guest operating system. These are the memory reclamation techniques:

  • Transparent Page Sharing (TPS)
  • Memory ballooning
  • Host-level (or hypervisor) swapping

Getting ready

To step through...