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Old 01-28-2008, 06:08 PM   #1
iAlta
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Virtual Machines: Practical? No! Fun? Yes!


I've been playing around with virtual machines, I don't see any real pracical use for it for me, but they are fun to play with.

When I installed Fedora 8 ontop of my OpenSUSE 10.3, I wondered "Why stop here?"

So I went on.

It was kinda hard to get DSL working, I had to use qemu, because it wouldn't boot with VirtualBox.

But now I made it, look:
http://tinyurl.com/36jljf
I don't know if that is the most practical way to post on linuxquestions.org...
 
Old 01-28-2008, 06:15 PM   #2
Simon Bridge
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Learning is a "practical use"... now you can run more than one VM on your box at the same time... see if you can network them. Normally you'd need to buy more hardware to learn about this
 
Old 01-28-2008, 08:37 PM   #3
gilead
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I have a VMWare image with Windows for Workgroups 3.11 for some work I did for my son's school. They still have a couple of boxes running some old stuff I did for them and I don't want to have a box set up just for the occasional call I get from them.

I also use it for Linux From Scratch installs and testing package builds for my Slackware installs. I also have one image that is non-persistent so I can test software that might do bad things to my box and recover just by re-starting.
 
Old 01-29-2008, 07:59 AM   #4
Hangdog42
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Not practical? Uh, yes they are. I've got Slackware running as the host on my laptop and I've got VMWare installed and running two clients, Windows XP and CentOS. I use the Windows client when I run into weird crap like a Webex session that won't run in Linux. Instead of having to reboot into Windows, I just start the virtual machine and I'm off and running. The CentOS VM is used for a project I'm working on where it will be the underlying OS. We'll be distributing the final product as a VM, making installation on the customer end absolutely trivial.

They are also HIGHLY practical from a security standpoint. If you run a webserver, run it in a VM so if you get cracked, you simply replace the image and you're back to where you were.
 
Old 01-29-2008, 10:55 AM   #5
Erik_FL
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Not everyone needs to use a virtual machine, but there are some practicaly uses.
  • Snapshot a "virgin" system to test installation of programs
  • Run games for an older OS
  • Support questions and problems for older operating systems
  • Run multiple operating systems at the same time and switch between them
  • Test network configuration and OS configuration for multiple virtual computers
  • Prepare a system image to install on some other computer
  • Restore files or an OS from a failed computer and export settings for programs
  • Browse the Internet in a closed system that can be reset to a saved state
  • Test boot CDs or DVDs
 
Old 01-29-2008, 12:30 PM   #6
iAlta
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It is true, what you say. I have for example use VirtualBox to test out distros... But I think it's kinda overkill.
But it's good for the CD budget, and you can feel good that you have saved some plastictrees...
 
Old 01-29-2008, 12:37 PM   #7
bowens44
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Quote:
Originally Posted by iAlta View Post
I've been playing around with virtual machines, I don't see any real pracical use for it for me, but they are fun to play with.
I find it to be very practical. I use a virtual instance of win xp for photoshop and a couple of other apps for which I haven't been able to find linux equivalents.
 
Old 01-29-2008, 07:01 PM   #8
ComputerGreek
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Not practical? Uh, yes they are.

I run Windows XP under QEMU (KVM) and it works faster than the native XP. At least that is how I experience it.

You can also run Windows Vista under QEMU (KVM) but the video card is a DOG.

See: Qemu (KVM) and Vista, at

http://www.linuxquestions.org/questi...vista.-616158/
 
Old 01-30-2008, 06:50 PM   #9
dracolich
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I have to say that they are practical. I have a Win2K VM in VirtualBox that's almost a clone of my original. I have a Win98 VM just for fun. I didn't make one for Win3.11 because I already did in DOSBox. I have Ubuntu and Fluxbuntu VMs because my dad got started with Ubuntu and it's useful to help answer some of his questions. I have a Slackware-1.1.2 VM just for fun. And I have a SLED10 VM for experimenting with to learn the SuSE way of things.

It can also be useful for testing bootable floppy and cd images without rebooting the host computer. It can be useful to test questionable software before installing it on the host. And a VM is completely self-contained inside one or two files. If you're using a Windows VM and it gets a virus it won't infect the host (unless you share infected files).

Quote:
Originally posted by ComputerGreek
I run Windows XP under QEMU (KVM) and it works faster than the native XP. At least that is how I experience it.
My Win2K seems faster, too, even with all the security stuff loaded. I think it's because everything runs inside a single file so there's little-to-no fragmentation and disk thrashing.
 
Old 01-31-2008, 12:04 AM   #10
ComputerGreek
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Quote:
Originally Posted by dracolich View Post
I think it's because everything runs inside a single file so there's little-to-no fragmentation and disk thrashing.
There would be less disk thrashing because the files are restricted to within a single file (the image), but this would be much like restricting the files to a separate partition.

It still uses the NTFS filesystem to distribute (bits of) files throughout the image, so I would imagine that fragmentation would be as usual.

I would guess that the basic IO and file manipulation routines are more efficient in Linux.

I really don't know what makes it seem to run better. It shouldn't, because Qemu/KVM only gets 1GB of RAM and Windows gets the full 2GB.
 
Old 01-31-2008, 01:35 AM   #11
AceofSpades19
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I would say its practical as long as you have the hardware to do it, if you have a pentium 1 with 64 mb of ram, its obviously not going to be practical, but if you have a modern machine with 1-2 gb of ram it would be pretty practical. According to Theo de Raat(I think thats his name) of Open BSD its not that secure because if the host machine gets compromised then all the virtual machines are at risk
 
Old 01-31-2008, 07:24 AM   #12
Hangdog42
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Quote:
According to Theo de Raat(I think thats his name) of Open BSD its not that secure because if the host machine gets compromised then all the virtual machines are at risk
The idea is that the host machine is never at risk because access to it is severely limited. Admins only essentially. Any more general access is through the VM and it should be almost impossible to crack through the VM to the host. I'm certainly interested in hearing about VM breaches, but I can't say I've ever come across one. And I also view Theo de Raat with a touch of suspicion. He has a fairly long history of saying some pretty inflammatory things just to stir the pot.
 
Old 01-31-2008, 11:45 AM   #13
AceofSpades19
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Quote:
Originally Posted by Hangdog42 View Post
The idea is that the host machine is never at risk because access to it is severely limited. Admins only essentially. Any more general access is through the VM and it should be almost impossible to crack through the VM to the host. I'm certainly interested in hearing about VM breaches, but I can't say I've ever come across one. And I also view Theo de Raat with a touch of suspicion. He has a fairly long history of saying some pretty inflammatory things just to stir the pot.
True enough, he does seem to like to stir things up alot, but I thought I would just put that in to see what you guys thought of it
 
Old 02-01-2008, 06:31 PM   #14
ComputerGreek
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Quote:
Originally Posted by AceofSpades19 View Post
but if you have a modern machine with 1-2 gb of ram it would be pretty practical.
I have run it with 512 MB (256 MB for KVM/Qemu) and it was quite acceptable.
 
Old 02-01-2008, 10:32 PM   #15
lord-fu
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Sure I find them extremely practical, there is a lot of wasted resources on the vast majority of machines out there so use them up. [market_this_as_green]Save the planet and all that good stuff.[/market_this_as_green] I was able to remove quite a few physical machines this year and make them virtual guests on my more powerful desktop. I have 3 running now on a Slackware machine myself.

Last edited by lord-fu; 02-01-2008 at 10:35 PM.
 
  


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