Monday, September 17, 2012

VMware Technical Questions and Answers and Interview FAQ -Part5- Download

41. What is a P2V conversion?

Virtualization is most frequently used for server consolidation. This is where physical servers are converted into virtual servers. This “physical to virtual” conversion process is commonly called P2V conversion. This process can be done manually but it is easier if you use a P2V conversion application. While this P2V (or Virtual machine Import) functionality may be built into the management interface for your virtualization product, there are also standalone P2V products such as VMware Converter (diagram shown below) and Vizioncore’s vConverter.

These P2V products connect to the physical server, copy all data from that physical server into a virtual disk on the virtual server, replace the drivers in the guest operating system with virtual drivers, and start the new virtual machine. In some cases, there is no downtime for end users of that server.

Similar to a P2V conversion, a V2V (virtual to virtual) conversion is where a virtual guest machine from one virtualization platform is converted to another virtualization platform.
42. What is VDI?

VMware describes Virtual Desktop Infrastructure (VDI) as “delivering desktops from the data center”. In other words, VDI is where enterprise desktop computers are virtualized, moved to the data center, then presented over the LAN or WAN to the end users. Once VDI is used, typically the end user devices are replaced with thin-client devices.

While VMware has a VDI product called VDM (Virtual Desktop Manager), VDI is not a product exclusive to VMware. Other VDI vendors include Citrix XenDesktop & Kidaro (now owned by Microsoft).

With VDI, virtual desktops are served by enterprise virtualization servers running products like VMware ESX, Microsoft Hyper-V, and Xen Server. With the addition of the VDI products, these desktops can be dynamically created, pooled & shared, or even accessed from a GUI menu, over a web page.

The graphic below, shows some examples of how VDI could be used and how it works.



43. What is SoftGrid?

Microsoft purchased Softgrid and has renamed it Microsoft Application Virtualization. With this software, you are able to virtualize your applications and deliver them over the network. With application virtualization, your software applications are never installed on the end user devices so there are never any software conflicts. Because of this, software testing is reduced, time to set up end user computers is reduced, and software troubleshooting is reduced. Overall, application virtualization is going to save time and money. Microsoft Application Virtualization competes with XenApp and VMware’s ThinApp

44.What are the best free virtualization options?
In my opinion, the best free virtualization options are:

For testing, development, and production server virtualization solutions for SMBs, I recommend VMware Server or Microsoft Virtual Server

For desktop virtualization on your own PC, I recommend Microsoft Virtual PC And for Linux hosts – Xen and KVM

45. What is VM Sprawl?

Because creating new virtualized servers is so quick and easy, many organizations have a problem with “VM Sprawl”. With VM Sprawl, the number of virtual machines (VM) running in a virtualized infrastructure increases over time, simply because of the ease of creating new VMs, not because those VMs are absolutely necessary for the business.

Concerns with VM sprawl are the overuse of the infrastructure if it is not needed and the cost of licenses for virtual machines that may not have been required.

To prevent VM sprawl, you should more carefully analyze the need for all new VMs and ensure that you are able to justify the cost of the infrastructure and the licenses for all new VMs created.

46. How many virtual machines can you run on one host?

As with many server performance questions, the answer to this question is “it depends”. You can run as many VMs on a single host as your hypervisor supports (usually that is a lot) and as you have server resources for (RAM, CPU, Disk, and Network).

Typically, on a desktop PC, you can run 1-3 VMs and on a Server you can run 10-50 VMs – depending on the application demands.

47. What is ThinApp?

VMware bought a company (Thinstall) who offered an application virtualization product. VMware renamed that product ThinApp. Similar in concept to Microsoft’s SoftGrid (now Microsoft Application Virtualization), ThinApp allows you to virtualize your applications and deliver them from servers in the data center. This prevents application conflicts, allows for easy end user device replacements, allows for easy software deployment and, overall, saves time and money.

48. Why is centralized storage so important for enterprise virtualization products?

Centralized storage (such as an iSCSI or FC SAN) is very critical to many optional virtualization features. For example, with VMware High Availability (VMHA), VMs are stored in a centralized shared data store. If an ESX Server goes down, those VMs are automatically restarted on another ESX host because that host can access them overt the centralized shared storage (SAN). Thus, while centralized storage isn’t required to use enterprise virtualization features, many of the advanced or optional virtualization features don’t work without it.

49. What are the best online resources for Virtualization knowledge?

However, there are also a number of other valuable Internet resources for virtualization information. They are: VM Blog VMware VMTN Blog Run Virtual - Virtualization

Petri IT Knowledgebase – Virtualization

50.What are the best training options for learning about Virtualization?

As virtualization is relatively new and there is a large following building for its use, there is a huge demand for virtualization training. Here are a few of my recommendations:
VMware Education – offers a strong classroom and online training program as well as a certification program

Train Signal – offers a 3+ virtualization related videos covering Microsoft and VMware video training. One of their best sellers is the VMware ESX Server video product.

Dell Virtualization Training – covering VMware products Citrix/Xen

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