Red Hat LINUX VIRTUAL SERVER 4.6 - ADMINISTRATION Manuale di Installazione Scaricare il pdf (Pagina 23)

Chapter 1. Introduction to z/VM and Linux 3

the z9 BC processors or later.

Virtual Machine Resource Manager (VMRM) detects when

memory is constrained and notifies the Linux guests, which can then adjust their memory

consumption to help relieve the memory constraint. In the previous major release, z/VM V5.2,

many memory contention issues were removed with the Control Program (CP) now using

memory above 2 GB for a much broader set of operations. Previously, guest pages had to be

moved below 2 GB for many reasons, for example, in both standard I/O and Queued Direct

I/O (QDIO). Now I/O can be done using buffers anywhere in real memory, and QDIO

structures can reside above 2 GB, as can most CP control blocks. These improvements offer

constraint relief for large-real-memory virtual server environments that are memory intensive

1.1 What is virtualization

Virtualization is the ability for a computer system to share resources so that one physical

server can act as many virtual servers. z/VM allows the sharing of the mainframe’s physical

resources, such as disk (DASD), memory (sometimes called

storage), network adapters

(OSA cards), and CPU (CPs or IFLs). These resources are managed by a

hypervisor. The

z/VM hypervisor is called Control Program (CP). When the user logs onto z/VM, the

hypervisor creates a virtual machine that can run one of many different operating systems.

The two operating systems that are discussed in this book are the z/VM native one, that is,

the Conversational Monitoring System (CMS), which can be thought of as a z/VM

shell. and

Linux. Virtual machines running Linux as guests of a z/VM host become the

virtual servers.

1.2 The philosophy adopted in this book

An important philosophy adopted in this book is to keep all the solutions simple. Albert

Einstein once said, “Everything should be made as simple as possible, but not simpler”,

which sums up this philosophy. This book aims to use the same clear and insightful

presentation.

Many books and papers discuss virtualization, but do not tell you how to accomplish

virtualization. The remainder of this book discusses how to perform this virtualization.

1.3 Choices and decisions made in this book

When deciding about installing, maintaining, and provisioning (cloning) Linux virtual servers

under z/VM, there are many basic choices to make. Here are some of the choices and

assumptions made in this book:

򐂰 Use of a cloning product versus using your own cloning process: Cloning products, such

as Aduva Onstage, Mainstar Provisioning Expert, IBM Tivoli® Provisioning Manager, and

IBM Systems Director, are outside the scope of this book. While these are all viable

solutions, the cloning described in this book allows you to create your own Linux images

without using such products. However, these products are more sophisticated than the

simple clone script and z/VM configuration described in this book.

򐂰 Directory Maintenance product versus the USER DIRECT file: The USER DIRECT file is

chosen over a directory maintenance product such as IBM DirMaint™ or CA VM:Direct. If

you feel that DirMaint as a directory maintenance product is better suited to your

enterprise, refer to Getting Started With Linux, SC24-6096 to configure z/VM; you can still

use this book to configure Linux.

1 2 ... 18 19 20 21 22 23 24 25 26 27 28 ... 295 296

Commenti su questo manuale

Nessun commento

Red Hat LINUX VIRTUAL SERVER 4.6 - ADMINISTRATION Manuale di Installazione Pagina 23

Commenti su questo manuale

Prodotti e manuali riguardandi Software di system management Red Hat LINUX VIRTUAL SERVER 4.6 - ADMINISTRATION