Shared Folders in VirtualBox

Shared Folders are a big advantage in both VirtualBox and VMware Player (>3.0.x). However I notice that in my direct neighborhood there is a unfamiliarity with it. And how to use it. That is, it turns out that a created shared folder is not mounted right a way in a started VM. So to help this out, a little how to.

To create a Shared Folder you have to go to the SharedFolders node in the VM Settings:

There you can click on the add folder button. Of course you can remove or edit existing ones.



Give here the path to the folder on your host. At the layout of the screen you could gues my host is a Windows 7. You can give in a Shared Folder name.
The other options (check boxes, I really need to do a reinstall of VB in English, however it was no option I've chosen consciously to install it in Dutch) are:

• Read only
• Auto Mount
• Make permanent

I check the the latter 2.
Although auto mount is checked, this does not count right away for running Linux guests. Therefor you have to do a restart.

Shared Folders are automounted in linux as /media/sf_<sharedfolder name>

So as root you have to

• create the folder
• ' change owner' it to root:vboxsf
• set " group writable" with chmod
• Then mount the folder

So:

makker@makker-lnx:~> cd /media
makker@makker-lnx:/media> ls -l
total 92
drwxrwx--- 1 root vboxsf  4096 Aug 25 17:07 sf_Data
drwxrwx--- 1 root vboxsf  8192 Sep 21 13:45 sf_Documents
dr-xr-xr-x 1 root root   16384 Sep 22 09:59 sf_Downloads
drwxrwx--- 1 root vboxsf 65536 Aug 23 14:26 sf_Music
makker@makker-lnx:/media> sudo mkdir sf_Projects
root's password:
makker@makker-lnx:/media> ls -l
total 96
drwxrwx--- 1 root vboxsf  4096 Aug 25 17:07 sf_Data
drwxrwx--- 1 root vboxsf  8192 Sep 21 13:45 sf_Documents
dr-xr-xr-x 1 root root   16384 Sep 22 09:59 sf_Downloads
drwxrwx--- 1 root vboxsf 65536 Aug 23 14:26 sf_Music
drwxr-xr-x 2 root root    4096 Sep 22 12:06 sf_Projects

makker@makker-lnx:/media> sudo chown root:vboxsf sf_Projects
makker@makker-lnx:/media> sudo chmod g+w  sf_Projects
makker@makker-lnx:/media> ls -l
total 96
drwxrwx--- 1 root vboxsf  4096 Aug 25 17:07 sf_Data
drwxrwx--- 1 root vboxsf  8192 Sep 21 13:45 sf_Documents
dr-xr-xr-x 1 root root   16384 Sep 22 09:59 sf_Downloads
drwxrwx--- 1 root vboxsf 65536 Aug 23 14:26 sf_Music
drwxrwxr-x 2 root vboxsf  4096 Sep 22 12:06 sf_Projects

To mount the folder use the command mount -t vboxsf <sharedfolder name> /media/sf_<sharedfolder name>
So:

makker@makker-lnx:/media> sudo mount -t vboxsf Projects /media/sf_Projects
makker@makker-lnx:/media> ls -l sf_Projects/
total 94
-rwxrwxrwx 1 root root  9776 Oct 12  2010 AIA Project in Amsterdam
....

Now, as you'll notice to use the shared folder by another user than root, you'll need to add that user to the vboxsf user group.

The easiest way to do that is to use the user-administration tool of your linux distribution.

To add it on the commandline, first list the groups you allready have:

makker@makker-lnx:/media> id
uid=1000(makker) gid=100(users) groups=100(users),6(disk),17(audio),20(cdrom),33(video),49(ftp)

Or:

makker@makker-lnx:/media> groups
users disk audio cdrom video ftp

Then use usermod (as root or via sudo) to add the group:

makker@makker-lnx:/media> sudo /usr/sbin/usermod -g users -G disk,audio,cdrom,video,ftp,vboxsf makker
makker@makker-lnx:/media> groups
users disk audio cdrom video ftp vboxsf

Mind that you have always a primary group indicated with lowercase '-g', and several secondary groups indicated with capital '-G' and a comma separated list (don't use spaces).

That's it.