Book Image

VMware vCenter Cookbook

By : Kostantin Kuminsky
Book Image

VMware vCenter Cookbook

By: Kostantin Kuminsky

Overview of this book

Table of Contents (15 chapters)
VMware vCenter Cookbook
Credits
Foreword
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Protecting host redundancy for significantly different hosts


Admission control helps to make sure there is spare capacity available in a cluster to keep the required level, redundancy, or reservations.

There are three types of policies available, which are as follows:

  • Number of host failures a cluster tolerates

  • Percentage of cluster resources reserved

  • Specific failover hosts

When the requirement is to be able to lose one or more hosts and still be able to keep all the VMs needed running, the Host failures cluster tolerates option works quite well unless the hosts you are trying to protect have significantly different sizes—memory and CPU resources available.

This option for different hosts results in reserving an excessive capacity based on the size of the largest host. Reserving more capacity than required in its turn results in wasting resources.

For clusters with differently-sized hosts, VMware advice is to use the percentage of cluster resources reserved option. This option ensures that a specified...