Book Image

Mastering KVM Virtualization

Book Image

Mastering KVM Virtualization

Overview of this book

A robust datacenter is essential for any organization – but you don’t want to waste resources. With KVM you can virtualize your datacenter, transforming a Linux operating system into a powerful hypervisor that allows you to manage multiple OS with minimal fuss. This book doesn’t just show you how to virtualize with KVM – it shows you how to do it well. Written to make you an expert on KVM, you’ll learn to manage the three essential pillars of scalability, performance and security – as well as some useful integrations with cloud services such as OpenStack. From the fundamentals of setting up a standalone KVM virtualization platform, and the best tools to harness it effectively, including virt-manager, and kimchi-project, everything you do is built around making KVM work for you in the real-world, helping you to interact and customize it as you need it. With further guidance on performance optimization for Microsoft Windows and RHEL virtual machines, as well as proven strategies for backup and disaster recovery, you’ll can be confident that your virtualized data center is working for your organization – not hampering it. Finally, the book will empower you to unlock the full potential of cloud through KVM. Migrating your physical machines to the cloud can be challenging, but once you’ve mastered KVM, it’s a little easie.
Table of Contents (22 chapters)
Mastering KVM Virtualization
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Index

Getting acquainted with Kernel Same Page merging


According to the KVM official documentation:

KSM is a memory-saving deduplication feature that merges anonymous (private) pages (not pagecache ones). Although it started this way, KSM is currently suitable for more than Virtual Machine use, as it can be useful to any application that generates many instances of the same data

http://www.Linux-kvm.org/page/KSM

As is well understood from the earlier quote, KSM is a feature that allows sharing identical pages between the different processes running in the system. We may presume that the identical pages may exist due to certain reasons—for example, if there are multiple processes spawned from the same binary or something similar. There is no rule like that though. KSM scans these identical memory pages and consolidates a Copy on write (COW) shared page. Well, if you don't know what I meant by COW, it is nothing but a mechanism by which, when there is an attempt to change a memory region that is...