Virtual Disk Questions

[merryoakparker]

I am currently running a dual boot with LMDE and Windows XP. The chief reason for my keeping XP is two programs which will not run on Linux and for which there seem to be no adequate replacement programs within the Linux repository. One of these I use at least daily; the second, frequently.

My questions: (please remember, although I'm mostly a lurker here, I'm really a noobie to LMDE.)

1) Should I set up a Virtual Disk (drive) in LMDE and put my Windows XP within it or vice versa?

2) If I put Windows XP into a Virtual Disk (Drive) in LMDE. will Clam AV protect it or should I continue to use my current Windows antivirus programs?

3) Will I need to run the usual Windows maintenance programs (defrag, scandisk, CCleaner, Superantispyware, Microsoft Malicious Software Removal Tool, etc.) on the Windows Virtual Disk (Drive)??

Thank all y'all,

Merryoakparker

[trapperjohn]

Hi,

I run Linux (Mint or Debian) as my native OS and XP in a VBox guest (It's faster). I have several Windows VMs.

Run a low overhead antivirus application in the Windows guest. A passive file-scanner that interogates files for signatures from the host will not flag maleware in realtime in the guest and will probably not detect signatures burried in the .vdi An antivirus program providing realtime protection in the guest will slow down your VM. Be sure to choose a virus checker that is light weight.

I perform all of the usual maintenance tasks for any given VM... Linux or Windows. (Soon, XP will have no updates.) When I know a system is updated and stable, I delete previous VM snapshots and create a new one called lastValidState.

I keep XP on a VM for the exact reason you provided - there are a couple of programs that I won't let go of. There a limited few applications that will run in a Windows native install but will not run in a VM because virtual hosts don't adequately provide certain hardware abstractions. Check your programs in a VM.

If you only use your VM for applications that do not require interaction with the outside world (for example, say you want to continue to use that $400 copy of Autocad you bought 10 years ago) then you can improve security and performance by removing virtual network adapters entirely, then completely disable antivirus, Windows update, and all other needless Windows services. Run msconfig and remove every extraneous startup application. But... agree with yourself that, from that point on, you will not install anything or cheat on your no network policy.

[SiKing]

I do not know what "Virtual Disk (drive)" is in this context.
Perhaps you mean VirtualBox (http://virtualbox.org/)? If that is the case, then your Linux system (including Clam AV) will not know about any programs that are installed there. Also, any system installed in VirtualBox will be susceptible to any problems that the same system would have installed on bare metal. So if you normally run all those maintenance programs on bare metal install, you should continue to run those on a VirtualBox as well. Well, maybe defrag is pointless.
HTH

[trapperjohn]

Well, defrag does come in handy when you want to zero free space then compact a dynamicaly alllocated vdi.

[SiKing]

I did not realize that defrag makes a difference on NTFS anymore, let alone on a VDI. But I have definitely been wrong before.

[trapperjohn]

File defragmentation, in the context of an XP VM, will not change performace (much if any) in the running XP guest. The vdi, being a file, does not have the read-head-seek latency that a hardware HDD has. So, for the (original) purposes of defraging to speed up the system, the proceedure is probably a waste.

But,when using a dynamically allocated vdi, there often come times when a user wants to compact the disk to a minimal size. The vboxmanage -compact procedure is most effective when contiguous zero space is greatest. The defrag, with luck, will move fragments out of contiguous free space. In the end, what we really want is unfragmented, zeroed free space. (By defragging the files, we're defragging the free space.)

Once upon a time, when Windows used FAT, there were utilities that would not only defrag a volume, they would pack the files together at the beginning of the disk. Sigh... those days are gone.

[SiKing]

I thought defrag will only move blocks around, so that individual files are packed together in a continuous manner. The freed blocks are only marked as free, but the data is not zeroed. Am I wrong about this? As such, vboxmanage -compact will still see those blocks are "used".

Once upon a time, when Windows used FAT, there were utilities that would not only defrag a volume, they would pack the files together at the beginning of the disk. Sigh... those days are gone.

I remember Norton Disk Utilities came with a fantastic user guide that went really in-depth on inner workings of FAT. Good 'ol days ... before the Age of IP insanity.