VirtualBox – Time Machine Friendly Virtual Machine Image Files

time-machinevirtual machinevirtualbox

I have a Windows 7 VirtualBox virtual machine. The disk image file is 30GB and is one large .vdi file. If I change anything inside that (even a few KBs), Time Machine wants to backup the entire 30GB file each time. Actually even if I just boot up the virtual machine, Windows makes some registry changes etc and even with 0 user/application level changes it triggers the full 30GB copy.

Is there a way to make a virtual disk image such that it's Time Machine friendly? So if a few KBs/MBs are changed, only those sectors are copied over?

Thanks
Sid

Best Answer

According to this blog post:

http://blog.matteocorti.ch/?p=331

creating a snapshot will do the trick:

simply create a snapshot of your machine. VirtualBox will then leave your hard disk image untouched and create a separate file with just the changes from the time of the snapshot.

Related Solutions

Time Machine – How to Backup Mounted Drive Image

Time Machine doesn't back up the contents of mounted drives for a few reasons. For example:

Mounted images can be very transient. If /Volumes/MyVolume exists on Monday but disappears on Tuesday, should it consider those files no longer existing and therefore remove from future backups? What if MyVolume comes back on Wednesday? Now it has to make a whole new copy of the contents again because it can't be sure the files are same ones it saw on Wednesday.
What if yesterday it's mounted as /Volumes/MyVolume but today it's mounted as /Volumes/OurVolume. Does Time Machine have to make a whole duplicate copy?
Backing up the contents of an image in addition to the image itself would waste space on your backup volume. You'd essentially be storing two copies of every file.

However, you can view past backups manually without taking the time to restore them. Browse to your Time Machine volume. For example, mine looks like this:

/Volumes/TimeMachine/Backups.backupdb/Hypatia/
    2009-11-27-163215/
    2009-12-11-075355/
    ....
    2010-06-22-004524/
        Hypatia/
            Applications/
            Developer/
            Library/
            System/
            Users/

Rather than using the fancy Time Machine interface, if you are looking for a specific version of an image (or bundle) file, I suggest looking through those dated folders and mounting the backup copies of your image file directly. You can open the folder that contains the dated folders then use the window's Spotlight search to find every copy of the image you're looking for (i.e., search for "NameOfImage.sparsebundle").

This way, you save the step of copying it back to your system drive and overwriting whatever is there. It's a little more tedious than using Time Machine's goofy interface, but it gets the job done.

Physical machine to virtual machine and place into VirtualBox

Have you tested Disk2VHD, from Mark Russinovich?

It's hard to think any way to convert a physical machine into a virtual one, and I think VirtualBox is able to use VHD files.

Best Answer

Related Solutions

Time Machine – How to Backup Mounted Drive Image

Physical machine to virtual machine and place into VirtualBox

Related Question