Friday, September 7, 2012

VMware Technical Questions and Answers and Interview FAQ -Part2

11.What is virtualization ?

Virtualization is the creation of a virtual (rather than actual) version of something, such as an operating system, a server, a storage device or network resources.

What are the types of virtualization?

12.What are the inherent benefits of virtualization ? primarily cost savings

allows multiple operating systems to be installed on a single server reducing the amount of hardware
Consolidating servers
also potentially reduces the amount of physical space that a company needs for its servers or data center.

13.What is a Hypervisor?

A hypervisor, also called a virtual machine manager, is a program that allows multiple operating systems to share a single hardware host. Each operating system appears to have the host's processor, memory, and other resources all to itself. However, the hypervisor is actually controlling the host processor and resources, allocating what is needed to each operating system in turn and making sure that the guest operating systems (called virtual mahines) cannot disrupt each other.

14.What is ESX Server?

ESX Server is VMware’s flagship enterprise server virtualization platform. It comes in two versions – ESX Server and ESXi Server where the latter has no service console and is the thinnest version available. ESX Server has many optional features like VMotion and VMHA (both discussed below) and some built-in features like the VMFS file system. Most end users purchase VMware ESX Server with some set of optional features in a package called VMware Infrastructure. ESX Server is managed by the VMware Infrastructure Client. Its centralized management platform is called Virtual Center.

15.What is Hyper-V?

Hyper-V is Microsoft’s flagship enterprise server virtualization platform. Hyper-V is a feature of Windows Server 2008 and it is required to be run on system with a 64-bit CPU. Its Hypervisor is about 100k, the Hyper-V role is about 100Mb, and Windows Server 2008, fully installed is multiple GB. The centralized management platform for Hyper-V is System Center Virtual Machine Manager.

16.Difference between ESX and GSX?

With VMware Workstation and GSX Server, the software sits on top of a host operating system such as Windows or Linux. With ESX Server, the software runs directly on the system's hardware, eliminating the need to install a base OS. In fact, ESX has its own OS. The software basically runs on its own Linux kernel, and Linux is quite beneficial to know when working with the product, although it's not an absolute necessity.

17.What is the hardware version currently in ESX4?

Version 7

18.What is VMware Workstation?

VMware Workstation uses virtual machine technology that is designed mostly for the power user. It allows you to run multiple operating systems on a single PC. The operating systems that can run under a VMware virtual machine can include Windows 2000, Windows XP, Windows 2003 Server, Novell Netware, and Linux.

 19. What are the fileExtensions? Extension

.log                  <vmname>.log or vmware.log

This is the file that keeps a log of key VMware Workstation activity. This file can be useful in troubleshooting if you encounter problems. This file is stored in the directory that holds the configuration (.vmx) file of the virtual machine.

.nvram             <vmname>.nvram or nvram
This is the file that stores the state of the virtual machine's BIOS.
.vmdk              <vmname>.vmdk

This is a virtual disk file, which stores the contents of the virtual machine's hard disk drive.

A virtual disk is made up of one or more .vmdk files. If you have specified that the virtual disk should be split into 2GB chunks, the number of .vmdk files depends on the size of the virtual disk. As data is added to a virtual disk, the .vmdk files grow in size, to a maximum of 2GB each. (If you specify that all space should be allocated when you create the disk, these files start at the maximum size and do not grow.) Almost all of a

.vmdk file's content is the virtual machine's data, with a small portion allotted to virtual machine overhead. If the virtual machine is connected directly to a physical disk, rather than to a virtual disk, the .vmdk file stores information about the partitions the virtual machine is allowed to access.

Earlier VMware products used the extension .dsk for virtual disk files.

This is a redo-log file, created automatically when a virtual machine has one or more snapshots. This file stores changes made to a virtual disk while the virtual machine is running. There may be more than one such file. The ### indicates a unique suffix added automatically by VMware Workstation to avoid duplicate file names.

.vmsd                          <vmname>.vmsd

This is a centralized file for storing information and metadata about snapshots.
.vmsn                          <vmname>-Snapshot.vmsn

This is the snapshot state file, which stores the running state of a virtual machine at the time you take that snapshot
This is the file which stores the state of a snapshot
.vmss               <vmname>.vmss

This is the suspended state file, which stores the state of a suspended virtual machine
.Some earlier VMware products used the extension .std for suspended state files
.vmtm              <vmname>.vmtm

This is the configuration file containing team data.
.vmx                <vmname>.vmx

This is the primary configuration file, which stores settings chosen in the New Virtual Machine Wizard or virtual machine settings editor. If you created the virtual machine under an earlier version of VMware Workstation on a Linux host, this file may have a .cfg extension

.vmxf               <vmname>.vmxf

This is a supplemental configuration file for virtual machines that are in a team. Note that the .vmxf file remains if a virtual machine is removed from the team.

.VMDK -- These files are the actual hard disk of the virtual machine itself, and tend to be the largest file within the folder. You can consider the size of this file to be roughly equivalent to the size of either the disk itself (if you've chosen to use preallocated disks) or the size of the data currently stored on that disk (if you use growable disks).

.NVRAM -- Consider this file the BIOS of the virtual machine.

.VMX -- With typically one VMX file per folder, this file holds the configuration information for the virtual machine in a text format. Unlike almost all the other files you'll see, these files can be edited using any text editing program, a process that is actually required for some functionality that is not exposed in the GUI.

.VMXF -- This file, in XML format, includes additional information about the virtual machine if it has been added to a team. If a machine has been added to a team and then later removed, this file remains resident. This file can also be opened and read in a text editor.

.VMTM -- For virtual machines actively participating in a team, this file stores information about that team membership.

.VMEM -- These files, which contain a backup of the VMs paging file, are typically very small or non-existent when the virtual machine is powered off, but grow immediately to the size of configured RAM when the machine is powered on.

.VMSN and .VMSD -- When snapshots are created for a virtual machine, these files are created to host the state of the virtual machine. The VMSN file stores the running state of the machine, what you could consider the "delta" between the VMDK at the point of the snapshot and what has been processed up until the present time. The VMSD stores information and metadata about the snapshot itself.

.VMSS -- If you've suspected the state of your machine, this file contains the suspended state of that machine. These files typically only appear when virtual machines have been suspended.
20. What are a host, guest, and virtual machine?

A host system (host operating system) would be the primary & first installed operating system. If you are using a bare metal Virtualization platform like Hyper-V or ESX, there really isn’t a host operating system besides the Hypervisor. If you are using a Type-2 Hypervisor like VMware Server or Virtual Server, the host operating system is whatever operating system those applications are installed into.A guest system (guest operating system) is a virtual guest or virtual machine (VM) that is installed under the host operating system. The guests are the VMs that you run in your virtualization platform.Some admins also call the host & guest the parent and child.

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