Well I have installed quite a few OS (Windows 7, Windows Server 2008, Linux Mint, Ubuntu, RedHat, Windows XP, SLES, SLED, CentOS, Windows Server 2003) on VMware and I have never had such trouble with graphics. I have never tried Gento on VM but I think it should work as well.

As far as I know as long as you assign sufficient RAM to VMs you should not have any issues with graphics. I have tried reducing assigned RAM once for a Linux system and then it wont let me install in graphical mode but yes after increasing the assigned RAM it worked.

The only suggestion that I can give is to check the hardware requirement for each OS and set up VM accordingly.

A virtual machine is emulating a complete PC, including graphics card. While modern CPUs have extensions to accelerate the emulation of a virtual CPU, there are currently no extensions for graphics cards. The virtual graphics cards use the OpenGL interface to access the physical graphics card, and do currently not deliver the full functionality and performance to run the "bigger" WMs with 3D effects.

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There are two issues with virtual machine graphics. One is functionality to emulate all the hardware features of a complicated graphics card. The other is how to achieve adequate performance. VirtualBox has some support for 3D graphics but won't support Windows Aero or 3D games for Windows. VMWare has better 3D graphics support but I don't know the exact capabilities.

Drivers for the guest OS are required when the OS does not have a driver for the emulated hardware. In some cases the virtual machine emulates a hardware device made by some company, and in some cases the virtual machine emulates hardware that is unique to the VM program. Guest drivers can support extra features such as screen resizing and mouse integration.

I'm not going to use Windows over VmWare, just two Linuxes, so its 3D capability is of no importance to me.

BTW, how much of performance real server looses when implemented as a virtual guest system (I'm learning terminology!;-) ), versus normal standalone installation? Can it handle as much of workload? I would expect some performance tradeoffs. Am I right?

Hi Kien,

Well a guest system does not looses any performance if implemented properly. I mean many companies are moving towards virtualization so if you implement it properly (I mean you install it on a high end VM software like VMware ESX that is the one I have tried on, with a high end Host machine say a monster machine of 16 CPUs and 64 GB RAM and TBs of hard disk space :-) ) with proper configuration as required by the server.

When you talk about the test environment you will feel a little difference because you have limitation when you installing it on a laptop or on a host machine at home. Here you try to accommodate many machines with low end host machine just to practice.

Depends
a) on your machine. If you have a CPU with hardware support for virtualization there will only be a slight loss of performance in comparison to run a native system.

b) on how much resources you are dedicating to the VM.

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If the Host OS has hardware support for virtual execution then you don't lose a lot of performance. The Guest OS does still share the CPU with anything running in the Host OS. On a Host OS with very little extra memory and no hardware support for virtual execution the performance of a Guest OS is greatly decreased.

Does it make a difference for a performance which virtual solution is used (Xen, VMware, Virtualbox), or they all use the same basic technology? I'm asking just out of curiosity, it not really important to me at this point.

I just thought I would reply to this:

A virtual machine does not necessarily emulate the host machine.

Some more primitive VMs actually don't pass any data "down the pipe" whatsoever, instead they actually emulate the circuitry of an entire physical PC (including the CPU) in software. QEMU is a popular example of such a VM. These VMs are, of course, far slower than those that use software trickery to use the CPU directly (or use hardware virtualization support found in some modern CPUs).

About your above question (in post #69), I don't know. Someone else can answer.

The difference in virtual solutions is how well they take advantage of hardware virtual features and how well they emulate the guest instruction set (if different than host CPU). The worst performance is when the guest instruction set has to be fully emulated by the host. For example, running a MIPS virtual CPU on an Intel X86 host CPU.

When the virtual solutions all use hardware virtual features and the Guest has the same instruction set as the Host OS there is very little difference in performance between solutions. The 3D graphics performance and disk I/O are areas where you will see more performance variations because they are not yet hardware assisted to a large degree. Disk I/O using DMA can be emulated by page remapping so there is usually still similar performance depending on the software efficiency.

The two major factors in choosing virtual solutions for me are the cost and the reliability. On the reliability scale, VMWare is probably the most reliable, Microsoft Virtual PC is a little less reliable, and VirtualBox is the least reliable. VirtualBox suffers from continual redevelopment and one must choose the version carefully to get one with the least problems and the needed features. I still prefer VirtualBox but I don't install every version that is available. VMWare is the most costly version, followed by VirtualBox and then Microsoft Virtual PC. VirtualBox costs more than Microsoft Virtual PC even though they are both free. The extra cost of VirtualBox is in time and testing to verify that one has a "good" version of it that fits the requirements. While there is less testing with Microsoft Virtual PC, it also lacks many features of VirtualBox.

Microsoft VirtualPC has a little bit worse performance than VirtualBox but it also supports older Windows Operating Systems such as Windows 95, 98 and ME better than Virtual Box. VirtualBox has slightly better performance than Virtual PC but only fully supports Windows NT through Windows 7 or Linux Guests. I haven't tested VMWare but it seems to have better support for 3D graphics and might be more suitable for playing 3D games.

My primary use of virtual machines is to run Windows XP on top of Windows 7 for software development. I don't use 3D graphics acceleration. I use features such as desktop integration, clipboard sharing, mouse integration virtual networking and shared folders. Sometimes I use a different virtual machine program to play Windows 95 games that don't require 3D graphics acceleration. I am starting to get some information from my brother who is testing VMWare for use with newer 3D games requiring graphics acceleration.

I hope that answers some of the questions but virtual machine software performance is very application specific. One really has to test with the exact host and guest. In some cases bugs can have a drastic and unexpected effect on performance.

Since the OP is asking because he wants to run Linux in a VM I think I have to point out that there is absolutely no support for Linux-guests in Microsoft's VirtualPC. So you simply don't get

Quite correct, only few older versions of Linux are supported by Microsoft Virtual PC. To run Linux in a VM, or to run a VM on Linux, VirtualBox is probably the best choice. This thread is wandering a bit off topic as well, since the original question was about Linux differences rather than virtual machines.

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I wasn't aware of Virtual PC solution by Microsoft, but my understanding is, that it cannot run Linux anyway.

mh, I worked with M$-Virtual-PC during my MCSA-course, if I remember correctly it can host Linuxmachines, but as TobiSGD stated it has no guestadditions for Linux. True is that it cannot run on Linux.

Markus