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Dive into the z/VM hypervisor

About this series

This series starts with a background on hypervisor types and system virtualization, and then describes the features of five hypervisors, their deployment processes, and the management issues you might encounter. Use this series as a simple starting point for understanding the hypervisor’s role in virtualization in the cloud or explore the individual articles to help you determine which hypervisor is best suited for your cloud needs: Introduction, PowerVM, VMware ESX Server, Xen, KVM

What to know to start

The z/VM® hypervisor is designed to help extend the value of mainframe technology across the enterprise by integrating applications and data while providing exceptional levels of availability, security, and operational ease.

z/VM virtualization technology is designed to allow the capability to run hundreds to thousands of Linux® servers on a single mainframe running with other System z® operating systems, such as z/OS®, or as a large-scale Linux-only enterprise server solution.

z/VM V6.1 and z/VM V5.4 can also help to improve productivity by hosting non-Linux workloads such as z/OS, z/VSE®, and z/TPF on the same System z server or as a large-scale enterprise-server solution.

z/VM supports Linux, z/OS, z/OS.e, Transaction Processing Facility (TPF), and z/VSE. z/VM also supports z/VM as a guest operating system.


The z/VM base product includes the following components and facilities:

  • Control Program (CP): CP is a hypervisor and real-machine resource manager.
  • Conversational Monitor System (CMS): CMS provides a high-capacity application and interactive user environment and provides the z/VM file systems.
  • TCP/IP for z/VM: TCP/IP for z/VM provides support for the TCP/IP networking environment.
  • Advanced Program-to-Program Communication/Virtual Machine (APPC/VM) Virtual Telecommunications Access Method (VTAM) Support (AVS): AVS provides connectivity in an IBM Systems Network Architecture (SNA) network.
  • Dump Viewing Facility: It is a tool for interactively diagnosing z/VM system problems.
  • Group Control System (GCS): GCS is a virtual machine supervisor that provides multitasking services and supports a native SNA network.
  • Hardware Configuration Definition (HCD) and Hardware Configuration Manager (HCM) for z/VM: HCD and HCM provide a comprehensive I/O configuration management environment.
  • Language Environment for z/VM: Language Environment provides the runtime environment for z/VM application programs written in C/C++, COBOL, or PL/I.
  • Open Systems Adapter/Support Facility (OSA/SF): OSA/SF is a tool for customizing the modes of operation of OSA hardware features.
  • REXX/VM: REXX/VM contains the interpreter for processing the REXX programming language.
  • Transparent Services Access Facility (TSAF): TSAF provides communication services within a collection of z/VM systems without using VTAM.
  • Virtual Machine Serviceability Enhancements Staged/Extended (VMSES/E): VMSES/E provides a tools suite for installing and servicing z/VM and other enabled products.

z/VM also offers the following optional features:

  • Data Facility Storage Management Subsystem for VM (DFSMS/VM): DFSMS/VM controls data and storage resources.
  • Directory Maintenance Facility for z/VM (DirMaint): DirMaint provides interactive facilities for managing the z/VM user directory.
  • Performance Toolkit for VM: Performance Toolkit provides tools for analyzing z/VM and Linux performance data.
  • Resource Access Control Facility (RACF) Security Server for z/VM: RACF provides data security for an installation by controlling access to it.
  • Remote Spooling Communications Subsystem (RSCS) Networking for z/VM: RSCS enables users to send messages, commands, files, and jobs to other users in a network.

Deploying virtualization

To deploy virtualization for z/VM:

  • Create logical partitions.
  • Install and configure z/VM in one or more logical partitions.
  • Create virtual machines.
  • Install and configure guest operating systems.
  • Configure virtual networks for the virtual systems.

Managing your virtual machines

z/VM manages virtual machines through the IBM Systems Director, the platform-management foundation that enables integration with Tivoli, and third-party management platforms. With it, you can:

  • Automate data center operations.
  • Unify the management of IBM servers, storage, and network devices.
  • Simplify the management of physical and virtual platform resources.
  • Reduce operational complexity and provides a view of the relationships and health status of IT systems.

You can even get a single view of the actual energy usage throughout your data center.

Choosing z/VM

On the pro side:

  • Ability to virtualize each LPAR into hundreds or more virtual machines.
  • Ability to virtualize processor, memory, I/O, and networking resources.
  • Dynamically configure processors, memory, I/O, and networking resources.
  • Maximize resources to achieve high system utilization and advanced dynamic resource allocation.
  • Experience advanced systems management, administration, and accounting tools.

On the con side:

  • You will probably need highly skilled, mainframe-trained IT professionals to maintain.