IBM ^ z/VM Module 1: Introduction The basic concepts and fundamental ideas of z/VM 2004 IBM Corporation IBM ^ Objectives What we should be able to do: Describe z/VM and its benefits as an operating system Describe a virtual machine and what it does Describe the differences between a first level guest and a second
level guest Define what is meant by virtualization technology List four hardware resources that z/VM virtualizes Name three examples of Virtualization and describe each List three advantages that can be obtained by using Virtual Machines 2004 IBM Corporation
IBM ^ What is z/VM? An operating system (VM = virtual machine) A hypervisor, which refers to a system that virtualizes the zSeries architecture environment Runs on the zSeries architecture created by IBM 2004 IBM Corporation IBM ^ z/VM as an Operating System A highly flexible debugging, testing and production environment especially for operating system development Has the ability to run multiple virtual machine images and architectures Can simplify the migration from one release to another
2004 IBM Corporation IBM ^ z/VM as an Operating System (2) Running an operating system in a virtual machine should be the same as running an operating system on a real processor... ... actually it's better than a real machine Storage, processors, and I/O devices should behave in the same way on a virtual machine as on a real one The z/VMs user interface is its Control Program (CP) commands e.g. display GPRs etc 2004 IBM Corporation IBM ^ General z/VM Environment
2004 IBM Corporation IBM ^ What are Virtual Machines? z/VM uses real resources to create virtual machines that include processors, memory, I/O devices, and networks Virtual machines run as if it was running on the real hardware Virtualization Technology is used to create the illusion of hardware components VM allows users to run multiple copies, and different types, of operating systems on the same mainframe system at the same time e.g. CMS is/was a single user operating system 2004 IBM Corporation IBM ^
Creating System Level ...Running VM under VM 2004 IBM Corporation IBM ^ z/VM Virtualization Technology Can reduce system costs for: Planning to do function testing of pre or early release OSs Purchasing run test copies on production machine- 1 license Installing new hardware test new software version running
test systems 2004 IBM Corporation IBM ^ Memory Virtualization This diagram shows the translation process. Several different levels of translation are needed: Machine Physical Virtual OS memory memory
virt to VM virtual to Real 2004 IBM Corporation IBM ^ Storage Virtualization DISKs Physical Storage Direct Access Storage Devices (DASD) are the main storage device Minidisks are the partitions of the DASD storage device-- make a big disk look like many small disks These
are the physical storage devices that can be virtualized to obtain virtual storage devices Virtual Storage Virtual disks are high speed disks that perform and are capable of the same operations as the physical storage devices If you have a CP failure or shutdown all virtual devices are LOST... they are simulated devices.. simulated by VM e.g. printer Virtual storage increase
performance and can increase total size of storage devices An in memory disk 2004 IBM Corporation IBM ^ I/O Virtualization I/O devices that can be virtualized: Ethernet NIC (network interface card) Game port controller
Serial controller (COM) Parallel controller (LPT) Keyboard controller I/O TO device that can be virtualized: Video adapter Mouse and keyboard
Console interface 2004 IBM Corporation IBM ^ Examples of Virtualization-VTAPES Virtual tapes You can define and use virtual tape drives as if they were real tape drives Like real tapes, virtual tapes can be:
Mounted Written Rewound Read Unloaded When a virtual tape is no longer required, it can be scratched Are simulated using Mini-Disks 2004 IBM Corporation IBM ^ Three Advantages of Using VM
Highly flexible environment Multiple machine images Many guest utilizing the same hardware concurrently Consolidates resources Cuts down on physical resources and space Condenses many operating systems into one server Reduces Hands On testing requirements 2004 IBM Corporation IBM ^ Important Building Blocks z/VM Integrated Facility for Linux (IFL) Dedicated Linux engine for processing only Linux workloads Supports: Linux applications Linux operating systems Linux operating system in conjunction with z/VM IBMs IFLs are managed by PR/SM as a logical partition with
dedicated CPUs 2004 IBM Corporation IBM ^ Important Building Blocks z/VM Logical Partitions (LPARs) Provide the ability to share a single server among separate operating system images Help create a secure computing environment Processors can be dedicated or shared Can have multiple LPARs per server (up to 15 LPARs in a z900 server and up to 30 LPARs in a z990 server) Allows separation of workloads on a single hardware platform 2004 IBM Corporation IBM ^ Virtual versus Real
Environments Virtual: (z/VM) Can be functionally richer than a real environment Simulates hardware that does not have to exist in the real system, such as virtual tapes Can share a single copy of an application with many users Real: (LPAR) Limits depending on the hardware Hardware necessary to
accomplish your task can be expensive Supports only one system 2004 IBM Corporation IBM ^ Operating Environments Logical Partitions (LPAR) Hardware partitioning that enables up to 30 "logical partitions in the z/Architecture
Each LPAR runs a separate operating system Each LPAR can run a different operating system Virtual Partitions (z/VM) zSeries virtualization technology e.g. Vtapes, Spool devices Supports large numbers of Linux images and other operating systems Provides management capabilities
Very flexible; great for server consolidation 2004 IBM Corporation IBM ^ Running z/VM on an LPAR Logical partitions (LPARs) can over time reduce costs and increase flexibility z/VM on LPARs gives users better security with more control Next foil has a Visual 2004 IBM Corporation IBM ^ How z/VM Fits with z/Architecture 4 partitions(LPARS) 2004 IBM Corporation
IBM ^ Key Concepts Virtual machines emulates hardware and allows multiple users to use the same hardware components The importance of virtual machines: Virtual machines (VM) run as they were running on the real processor Can use hardware that does not have to exist in the real system by simulation and virtualization Virtual Machines can share a single copy of an application
2004 IBM Corporation IBM ^ Key Concepts continued What is Virtualization Technology: With virtualization technology, z/VM users can easily create many virtual machines consisting of: Virtualized processors Virtualized memory simulate real memory to virtual machine Virtualized storage- mini-disks, simulated disks e.g. paging space Virtualized I/O resources- network
These can reduce administration costs and the overhead of planning, purchasing, and installing new hardware to support new workloads. 2004 IBM Corporation IBM ^ Key Concepts continued The different types of environments: Logical Partitions (LPARs) Each of which runs a separate operating system Virtual Partitions (z/VM) Support for large numbers of Linux images and other systems
operating Running z/VM on a LPAR z/VM on LPARs gives users better security with more control 2004 IBM Corporation IBM ^ Conclusion While z/VM has proven itself as an advanced technology: cost effective tool for server consolidation. Linux running on IBM mainframes has created a new demand for z/VM. z/VM provides the ability to share hardware and software. Gives the users flexibility to respond to business challenges. 2004 IBM Corporation
