Shared Folders in Virtualbox

Question

I have a Win7 box with an Ubuntu 10.10 VM accessed in Virtualbox.

The Ubuntu install has the ex4 filesystem. Can I access the shared folders in both Windows and Ubuntu without corrupting the data?

I made this mistake when dual-booting my laptop and made changes to a folder in Ubuntu. When I tried accessing that data in Windows, the access time was very slow, basically about 10% of normal. The only way I could fix it was to restore the data from backups and not make changes in Ubuntu.

If I do this with the shared folders, will the same thing happen?

Answer 1

What you're reporting is very strange. I almost always use the same "downloads" and "documents" folders from both Windows and Ubuntu, and have never experienced slow downs from either OS. I have kept both of these directories on an external hard drive that is formatted as NTFS.

Additionally, I have used Ubuntu VMs from within Windows in the past, and still use a Windows VM from within Ubuntu, with shared folders on all of them, but never experienced any discrepancies in access times.

Why you ran into such a problem before is beyond me, but like "Centaurus A" suggested, try copying a few files over at first, and if it seems OK, then you know you're safe. If not, then you might want to ask around a bit more about why the slow down happens in the first place and how it can be prevented, as it isn't supposed to happen.

Answer 2

Don't see why there would be a problem; however, it would be easy enough to test by copying a few files to a shared folder. If the shared folder versions are problematic you would still have the originals.

Answer 3

There always is some risk for data corruption when accessing files simultaneously from one and the other OS. The shared folder concept of Vitual Box is pretty safe in this context, however still you will have problems e.g. with permissions when writing files for Ubuntu from Windows, and vice versa. In addition when the virtual machine crashes while writing to a file in a shared folder unexpected things may happen.

Using shared folders from Virtual Box is an easy to setup and safe way to gain access and share files between host and guest machines. This can even be acchieved during runtime. I never encountered a problem by doing so. However shared folders are limited as these folders need to be located on the host machine - that is NTFS/Windows in your case. There is no safe way to access files of your virtual Ubuntu guest from the Windows host.

An alternative to exchange files from one OS to the other would therefore be running network file sharing e.g. by using Samba and let network technology care for permissions and your data integrity. You then can also define shares from your Ubuntu files but please don't share Ubuntu system files with a Windows OS.