I have spent some time playing with Virtual Machines, I got interested in these way back when UML (User Mode Linux) was a big thing. That broke for me when I went from Mandrake to Fedora so that is one that will not be discussed here, other than to mention it is available.
I am only interested in FREE Virtual Machine software. I am playing with VM’s for personal use only, not in a business, so can’t justify a commercial one.
I haven’t been able to find one that does all yet, but I will discuss
- XEN
- Microsoft Virtual PC 2007
- VMPlayer
- QEMU
- Virtual Box
I’ll cover off the ones that fell short for one reason or another first.
XEN can be covered off quickly, from the documentation it looks good but my play server did not have enough memory in which to run virtual machines. Also it was at the time I looked at it Linux specific so not ideal for my needs. Long term XEN is likely to be very usefull, although now KVM is being introduced into Linux builds I’m not committing either way.
Microsoft Virtual PC 2007 I have discarded within a couple of hours of installing it. It probably runs windows well, but had real trouble with Linux and could not handle Solaris 10 x86 at all; no use to me whatsoever.
VMPlayer was probably the first I used seriously, but outgrew. I was not interested in purchasing the commercial offering.
So, onto the two remaining VM’s. Theres a bit more detail on these as I am still using them both. Both allow multiple disk images to be used by the VM and quite a few combinations of network settings that should meet every need.
QEMU has worked extremely well for me. One of it’s main highlights for me is that you can just copy the windows binaries onto a Windows PC and run it without needing to allow it to create any Windows Registry entries (although I don’t use the KQemu accelerator in this way but it’s still pretty fast) which means I can just copy my images onto the work laptop and run them without needing administrator rights. If you do install the whole application from the installation .exe you will get the registry entries and the KQemu accelerator, personally I haven’t seen any great performance improvement from using the accelerator.
QEMU is available for both Windows and Linux which suits my needs. It also fully supports VMWare’s .vmdk image file format and yes I have copied my VMPlayer images across and booted sucessfully under QEMU. As well as .vmdk image files there is a proprietory QCOW format that supports both compression and encryption of your disk image files.
QEMU has sucessfully let me run Solaris 10 x86 0606 release (with a lot of work due to a Solaris java bug and having to search the web for solaris network drivers for it), OpenSolaris with no problems, Fedorea Core 3 and Core 6; plus my old Windows 98 system has been retired and Windows 98 is in a QEMU VM. The Solaris 10 x86 image is the one getting the most use, and I am happily copying that between Linux and Windows XP machines without any problems.
However, I had a lot of trouble with getting PCLinuxOS to install under QEMU, only because QEMU couldn’t manage the graphics displaying the boot menu so I couldn’t see what to pick, once I found the right option and booted ‘blind’ the rest of the install was OK; and no worries because I didn’t like PCLinuxOS and deleted it anyway.
Virtual Box is the next on the list. This is apparently based upon the QEMU engine and so obviously functions well. It has a more professional ‘front end’ than QEMU as its aimed at a different segment (ordinary users that don’t like command line), plus it is a commercial offering for business use; free for personal home use though.
Graphics handling seems a little better than QEMU, in that Virtual Box could display the PCLinuxOS boot menu list. Also the point and click device configuration of the GUI ‘front end’ makes it a lot easier to use. There are still some command line commands you will need to use to fully use this VM though.
A drawback of Virtual Box is that it uses it’s own proprietory disk image format. While the latest release is supposed to be able to use pre-existing .vmdk images I have never been able to get this to work. Another drawback for my personal VM use is that Solaris 10 x86 doesn’t seem to have any drivers available for the emulated network card used by Virtual Box, so I have a fully working Solaris 10 image with no networking. Various flavours of Linux had no problems however.
So in summary, for my personal use QEMU is the only one that fully meets my needs at present; if only because Solaris is missing drivers rather than any issue with Virtual Box itself. Also the QEMU QCOW image format can be recompressed when large changes are made saving a lot of space, and I have found a use for it’s encrypted disk images. For ordinary home users who don’t want to know what is going on in the background Virtual Box is the way to go.
I will probably cover QEMU and Virtual Box in more detail in later posts, as this summary does niether one proper justice.
