Remote DVD booting
Q I have a Pentium 3 laptop with not much RAM, but it does have a DVD drive. I have a Pentium 4 PC with 1 GB RAM, no DVD drive and VirtualBox installed. Both laptop and PC are networked and I normally access the PC from the laptop via SSH. I want to run distros from in VirtualBox but the PC only has a CD drive and I'd prefer not to copy the DVD ISO image on to hard disk. So I installed NBD (network block device) software on the laptop (server) and PC (client) and do this: 1 Boot laptop 2 Boot PC 3 Put DVD in laptop DVD reader 4 Start nbd-server on laptop 5 Start nbd-client on PC 6 Mount /dev/nbd0 to /mnt/dvdrom on PC 7 Start VirtualBox and start a guest like Puppy from the DVD by using the CD/DVD mount ISO image tab under details (the ISO images on the DVD are in the Distro directory) 8 Enjoy Puppy (or whatever) Now, you might say, I could burn the Puppy ISO to CD and boot the CD from the host CD drive (which would save a lot of network traffic and may be faster). But if I have a distro that is on the DVD, like OpenSUSE 11.0, how do I get VirtualBox to boot the remote DVD?
A As far as I can tell, what you want to do is not possible with VirtualBox. It does not allow you to enter a device node for the DVD, and editing the configuration file to use /dev/nbd0 instead of /dev/cdrom does not work either. Similarly, telling it that /dev/nbd0 is an ISO image does not work either. In each case, VirtualBox does not recognise the device as a CD/DVD. However, the latter approach does work in VMware. Setting /dev/nbd0 as the CD/DVD device doesn't work, but setting it as an ISO image does. You could use VMware Workstation or VMware Server instead of VirtualBox to run distros on the DVD, or you could copy the DVD to an ISO image on the PC. I know you said you didn't want to do this, but it's a more efficient way of doing it than using NBD. Not only would the transfer be faster, although that would be offset by having to copy the whole DVD, but it only has to be done once and in the background while you are not trying to run or install the distro on the virtual machine. You can copy the ISO image directly from the DVD drive to the PC by running this command on the laptop:
cat /dev/dvd | ssh -c blowfish ip-address "cat >~/dvd.iso"
where ip-address is the address (or hostname) of the PC. The -c option switches SSH to the relatively insecure blowfish cipher. Although less secure, and not recommended for use on public networks, it is faster and reduces the load on both computers when transferring over a private network. You can then use the ISO image in VirtualBox, and it will run a lot faster than an NBD mount would have. The third option, and surely the simplest, is to fit a DVD-ROM drive to the PC. Your differentiation between this and the laptop indicates that this is a desktop computer, in which case a standard DVDROM drive can be bought for around £10 from an online supplier or a local computer fair, or a DVD re-writer for around £15. Unless there are good technical reasons for not replacing your CD-ROM with a DVD drive, I would suggest this as the fastest and most hassle-free solution.
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