On Saturday 28 November 2009 14:49:44 Mike Cloaked wrote: > Interesting replies - thank you - but noticeable that the fedora provided > facility of kvm has been mentioned by no-one! As others can say, it requires appropriate hardware, and is a bit rough on the edges. Other than that, the user interface for setting up a VM is not as user- friendly as the one in VirtualBox, hence my suggestion to use the latter, especially if you are a newbie to this. > Additionally can you experts tell me whether you can use usbkeys in the VM, In order to have full support for USB you need to use the closed-source VirtualBox from SUN (they have their own yum repo that serves it, look up on www.virtualbox.org). The difference between the closed and open source version is minimal, and consists mainly in support for USB and remote-desktop facility. In other words, install the SUN closed source version, and you have USB. > and also whether or not there is communication out of the VM onto the > network interface? Of course there is :-) . This is a bit complicated subject, there are four conceptually different ways of setting up networking for the virtual machine. Setting any of them up amounts just to an appropriate click in the wizard, but you need to understand how each functions and decide which is best for you. Only one can be set up for a given VM. They are as follows (N.B. I don't know exact names, I'm writing this from memory): 1) "Bridged network" --- your VM will have an independent network device which is "connected" to your ISP directly, on equal footing as your host computer (in reality the same cable/wireless is used, but that is not important). The upside is that it gets to use DHCP and all in the same way as provided to you by your ISP (or router, or whatever you are actually connected to). The guest is visible from the Internet as much as your host machine is. The Internet is visible from the guest as much as it is from the host. The downside is that all communication between your host and guest machines goes through that router: from your VM through host cable to the router and back through host cable to the host network card. This can be a bit inefficient if you have a slow connection and want to transfer inordinate amount of data between host and guest. You can also catch a virus/worm/whatever from the Internet if your guest does not have a proper firewall and stuff. 2) "Virtual NAT" --- your host will be provided with an additional virtual ethernet device, connected to a virtual switch which is connected to the guest. Imagine that you have two boxes and a switch --- both are connected to each other through a switch, and one (the host) is connected to your ISP with another eth card. That is the setup. The virtual switch provides DHCP for both host and guest (it is automatically set up to not interfere with your ISP's DHCP), sets up host as the guest's gateway and all. The upside is that you have a 1GBit connection between host and guest, regardless of any physical network. The guest is visible only from the host, not from the Internet, while Internet is visible from both (IOW, the virtual switch provides NAT for guest). You cannot catch a virus by just being connected, you need to do something stupid yourself (such as visiting suspicious websites with Internet Explorer or such). I recommend this for simple home use. 3) "Host-only network" --- same setup as virtual NAT, just guest is not allowed to access the Internet. It can see only the host, nothing else. 4) "No networking" --- obvious. Since you are a first-timer, go with virtual NAT, and don't worry about anything. :-) > Another point I am interested in is whether it is possible to drop a file > using the desktop file manager gui from Fedora into the XP VM window and > open the file in an app within the XP VM? I'm not sure about drag&drop, as I never use it (even in Linux itself). What you can surely do is to save the file into a shared folder and then drag&drop it from within the VM. It can amount to total of two drag&drops: one on the host (to get the file from the attachment into a shared folder) and one on the guest (to get the file from the shared folder into an app). File sharing is done via samba, you get the "Network Neighborhood" and all that in XP for the virtual network. It is not on by default, you need to set it up (this was mentioned in the thread). There is also one very useful thing --- copy/paste mechanism works across host/guests, albeit only for text-only contents AFAIK. Copy text here, paste it there, as if on the same machine. This becomes available (along with many other things) once you install "guest additions", custom drivers for the guest that make life better and easier. :-) > I'd like to know what the limits are for using the VM before going down the > road of setting it all up. Imagine two computers connected in a LAN. Anything that you can do with those, you can do in virtualized environment. In addition to that, you have some flexibility that is impossible to have with two physical computers: * ability to copy/paste across hosts/guests * ability to share same set of speakers and the same display * ability to have custom desktop resolution on guest in order to fit the geometry of the host's window that displays it * ability called "seamless mode", where windows from both host and guest are displayed in host's window manager --- the guest doesn't have its own "desktop", but shares it with the host; very very neat thing * ability to use only as much actual disk space as really needed by VM --- the virtual hard-disk is nominally say 10GB, but the actual file containing it is only as large as the total data written on that disk by the guest, so no free space is wasted --- the file just grows as the guest writes data to the disk * ability to add/remove hardware parts on the guest without a screwdriver and getting hands dirty * probably even more... > Additionally if anyone has used kvm how does qemu feature in this scheme - > is it needed at all for running an XP VM? QEMU is the actual emulator engine which is used in conjunction with KVM to provide virtualization. That is what you are running if you use Fedora's virtmanager. VirtualBox doesn't use it, it has its own emulator. > I can see that VirtualBox is recommended by people who have used it but I > would like to be able to compare VirtualBox with KVM in terms of not only > ease of setting up, but also performance and usability once it is set up. For normal desktop usage (opening files in Word and such) performance between VB and KVM is practically identical, provided the appropriate hardware for KVM. If your hardware does not support virtualization, QEMU will work in all- software emulation which is *terribly* slow, while VB has a kernel module which gives almost equal performance as if you had hardware support. QEMU did have such a kernel module up to some time ago, but support for it was dropped due to conflicting with support for KVM. That's when most users who do not have appropriate hardware dropped KVM/QEMU and went for VirtualBox. Note also that KVM/VB user experience is mostly identical to running XP natively on hardware, if you give it at least 512 MB of RAM. The performance decreases substantially for processor-intensive operations (math calculations, video production, virus scanning, etc.), but you should not use a virtual machine for those things in the first place. If you decide to face the Internet with a VM, you'll probably install some virus scanner, and that will be the biggest hog on the machine. Most of the other things are smooth. I suggest that you go to www.virtualbox.org and read all the docs available, you'll learn all that you want to know, and find out even more. Then try out one XP install just for fun, and see how it goes for you. Just remember to install guest additions once XP is up, since without it the desktop performance will be quite poor. Finally, in addition to VirtualBox and KVM/QEMU, there is also VMWare. However, it is proprietary and kernel modules break often due to frequent kernel upgrades in Fedora. Therefore I don't recommend it for usage within Fedora. OTOH, it does provide the best hardware support for the guest --- you can connect to the guest practically anything available on the host --- usb, webcams, bluetooth, FireWire, various card readers, and all that... HTH, :-) Marko -- fedora-list mailing list fedora-list@xxxxxxxxxx To unsubscribe: https://www.redhat.com/mailman/listinfo/fedora-list Guidelines: http://fedoraproject.org/wiki/Communicate/MailingListGuidelines
