5 Ways VMware vSphereChapter1. Improves An Introduction Backup and to VMware Recovery Virtualization CONTENTS CONTENTS..............................................................................................................2 INTRODUCTION......................................................................................................2 A BRIEF HISTORY OF VMWARE ..............................................................................3 VIRTUALIZATION ARCHITECTURE...........................................................................4 THE HYPERVISOR............................................................................................................................4 RINGS IN VIRTUALIZATION..............................................................................................................7 CPU SCHEDULER............................................................................................................................9 DIFFERENCES BETWEEN ESX & ESXI.............................................................................................9 WHAT IS A VIRTUAL MACHINE?...........................................................................12 ENCAPSULATION.......................................................................................................................... 12 VIRTUAL MACHINE HARDWARE ................................................................................................. 13 VIRTUAL MACHINE FILES ............................................................................................................ 14 VIRTUAL DISKS ............................................................................................................................ 18 VIRTUAL MACHINE MANAGEMENT .....................................................................20 THE VIRTUALIZATION LAYER ....................................................................................................... 21 HOW VIRTUAL MACHINES DIFFER FROM PHYSICAL SERVERS....................................................... 21 WHY VIRTUAL MACHINES REQUIRE VIRTUAL TOOLS ................................................................... 23 SUMMARY ...........................................................................................................25 ABOUT THE AUTHOR............................................................................................25 ABOUT THE SPONSOR..........................................................................................25 INTRODUCTION Virtualization is not just a fad and is definitely here to stay with most companies either currently using it or planning to in the near future. Running servers as virtual machines just makes sense on so many different levels when you factor in all the great benefits that they provide. Virtualization technology continues to mature at a very rapid pace with VMware leading the pack in almost all areas with their advanced features and widespread popularity. In this chapter we will cover some of the key concepts of virtualization and explain the different types of virtualization as well as go into detail into what a virtual machine actually is. We’ll also cover how virtual machines differ from traditional physical servers and why managing virtual machines requires a different mindset as well as the usage of applications designed specifically to work with virtual environments. Page | 2 5 Ways VMware vSphereChapter1. Improves An Introduction Backup and to VMware Recovery Virtualization A BRIEF HISTORY OF VMWARE VMware basically invented x86 server virtualization with their release of Workstation 1.0 in 1999 followed by ESX (Elastic Sky X) 1.0 and GSX (Ground Storm X) 1.0 in 2001. In 2003 VMware introduced VirtualCenter 1.0 with their groundbreaking new VMotion feature to migrate running virtual machines between hosts without interruption. In 2004 VMware released ESX 2.5 which was another major release for ESX. VMware Infrastructure 3 (VI3) came out in June of 2006 and was a major new release for VMware which introduced big new features like High Availability (HA) and Distributed Resource Scheduler (DRS) as well as a completely overhauled version of VirtualCenter (2.0). In 2007 VMware introduced their new hypervisor platform, ESX 3i that designed to eventually replace ESX. ESXi was designed with a much smaller footprint due to its smaller management console compared to the large Service Console that ESX uses. As a result VMware touted the new feature of being able to boot and run ESXi from a 1GB flash drive. Also in 2007 VMware released their next version of ESX (3.5) and VirtualCenter (2.5) that had more big new features like Distributed Power Management (DPM) and Storage VMotion. In 2008 VMware renamed ESX 3i to ESXi and announced they were going to give away the feature limited, entry level version of ESXi for free. This was mainly done in response to Microsoft making the move to give Hyper-V away for free. Also in 2008 VMware did some major product renaming and started to embrace the “v” naming convention for many of their products. As a result VirtualCenter was renamed to vCenter Server and the other management and automation products were all given the vCenter name as well (i.e. vCenter Lab Manager). In May of 2009 VMware released their much anticipated and biggest release yet, vSphere 4.0. This release was packed with new features and enhancements including the new Fault Tolerance (FT) feature, vStorage APIs, Distributed vSwitches, Host Profiles and much more. The vSphere 4.0 release was followed up by vSphere 4.1 which was released in July 2010 and as usual VMware packed more great features into it including Storage & Network I/O control as well as enhancements to many existing features. vSphere 4.1 also signaled the end of the road for ESX as VMware announced that 4.1 would be the last major release to include ESX and VMware would instead focus their development efforts on ESXi. Page | 3 5 Ways VMware vSphereChapter1. Improves An Introduction Backup and to VMware Recovery Virtualization VIRTUALIZATION ARCHITECTURE Virtualization is a very general term for simulating a physical entity by using software. There are many different forms of virtualization that may be found in a data center including server, network and storage virtualization. When talking about server virtualization there are many unique terms and concepts that you may hear that are part of the technology that makes up server virtualization. In this section we will cover some of those concepts as well as explain some of the other forms of virtualization. The Hypervisor The hypervisor is essentially the brains of server virtualization and in ESX & ESXi it is also known as the VMkernel. A hypervisor is a program that allows multiple operating systems to share a single physical hardware host. Each guest operating system (virtual machine) running on the host appears to have exclusive access to the host’s processor, memory and other resources. However, the hypervisor is actually controlling the processor and other host resources and only allocates what is needed to each guest operating system while simultaneously ensuring that each guest operating system is isolated from the others and cannot disrupt each other. In this way each VM is living inside its own small little ecosystem inside the host, blissfully unaware that its home is actually shared with many other tenants. An analogy for this is that while a physical server may be considered a standalone house a virtual host is more of a townhouse building. Before Virtualization Operating System After Virtualization encapsulated inside a virtual machine There are two different types of hypervisor models, the first are considered bare-metal or type-1 hypervisors and the others are considered hosted or type-2 hypervisors. The characteristics of each type of hypervisor are listed in the below table. Page | 4 5 Ways VMware vSphereChapter1. Improves An Introduction Backup and to VMware Recovery Virtualization HOSTED HYPERVISOR CHARACTERISTICS BARE-METAL HYPERVISOR CHARACTERISTICS Requires a host operating system Installs directly on the bare metal of a (Windows/Linux/Mac), installs like an physical server application Virtual machines can use all the Virtual machines’ resource usage can hardware resources that the host can be limited by advanced resource see controls Maximum hardware compatibility as Runs on a narrower range of the operating system supplies all the hardware due to limited driver hardware device drivers support Overhead of a full general-purpose Because there is no overhead from a operating system between the full host operating system virtual machines and the physical performance is 83-98% of native. hardware results in performance 70- There is a small bit of overhead from 90% of native the virtualization layer of the hypervisor Limited feature support Many advanced features for resource management, high availability and security Because of less overhead of the virtualization layer, bare-metal hypervisors support more VMs per physical CPU than hosted hypervisors do. In VMware’s line of products their bare-metal hypervisors are ESX & ESXi, and their hosted hypervisors are Workstation, Server, Fusion and Player. Hosted Virtualization Host O/S between Bare-metal Virtualization virtualization layer and hardware Page | 5 5 Ways VMware vSphereChapter1. Improves An Introduction Backup and to VMware Recovery Virtualization The VMkernel is considered a microkernel as it has the bare minimum of software code to provide