virtualbox.org

I've a question about vdi: I had create a dynamic vdi, with max 160 GB. Some weeks later I had my vdi file increased to about 30 GB (starting from 16GB when all programs were installed). So i tried to reduce my vdi file size, and I've done a zero fill with sdelete. Now, I've done modifyhd with --compact option to reduce effectively zero filled space. Now my vdi take about 160GB (zero filled space) and size is not reduced! Why does it happen? How to effectively reduce size of vdi file?

You can't have used sdelete and/or "modifyhd --compact" properly if that was your result.

I suggest that you compact with CloneVDI instead. You should find it simpler to use, and several orders of magnitude faster, because there's no need to use sdelete.