Book Image

vSphere High Performance Cookbook

Book Image

vSphere High Performance Cookbook

Overview of this book

VMware vSphere is the key virtualization technology in today's market. vSphere is a complex tool and incorrect design and deployment can create performance-related problems. vSphere High Performance Cookbook is focused on solving those problems as well as providing best practices and performance-enhancing techniques. vSphere High Performance Cookbook offers a comprehensive understanding of the different components of vSphere and the interaction of these components with the physical layer which includes the CPU, memory, network, and storage. If you want to improve or troubleshoot vSphere performance then this book is for you! vSphere High Performance Cookbook will teach you how to tune and grow a VMware vSphere 5 infrastructure. This book focuses on tuning, optimizing, and scaling the infrastructure using the vSphere Client graphical user interface. This book will enable the reader with the knowledge, skills, and abilities to build and run a high-performing VMware vSphere virtual infrastructure. You will learn how to configure and manage ESXi CPU, memory, networking, and storage for sophisticated, enterprise-scale environments. You will also learn how to manage changes to the vSphere environment and optimize the performance of all vSphere components. This book also focuses on high value and often overlooked performance-related topics such as NUMA Aware CPU Scheduler, VMM Scheduler, Core Sharing, the Virtual Memory Reclamation technique, Checksum offloading, VM DirectPath I/O, queuing on storage array, command queuing, vCenter Server design, and virtual machine and application tuning. By the end of this book you will be able to identify, diagnose, and troubleshoot operational faults and critical performance issues in vSphere.
Table of Contents (15 chapters)
vSphere High Performance Cookbook
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Keeping memory free for VMkernel


The amount of memory the VMkernel will try to keep free can be achieved through the Mem.MemMinFreePct parameter. MemMinFreePct determines the amount of memory that the VMkernel should keep free. vSphere 4.1 introduced a dynamic threshold of the Soft, Hard, and Low state to set appropriate thresholds and prevent virtual machine performance issues, while protecting VMkernel. The different states, based on %pRAM which is still free, determines what type of memory reclamation techniques are being used.

For MemMinFreePct, using a default value of 6 percent can be inefficient when 256 gigabyte or 512 gigabyte systems are becoming more and more mainstream. A 6 percent threshold on a 512 gigabyte results in 30 gigabyte idling most of the time. However, not all customers use large systems; some prefer to scale out rather than to scale up. In this scenario, a 6 percent MemMinFreePct might be suitable. To have the best of both worlds, VMkernel uses a sliding scale to...