virtualbox.org

My virtual machine indicates that I do not have enough disk space, and since I initially selected a dynamically increasing drive, I was wondering why this is always happening.
Do I need to re-configure the partitions within the virtual machine, not just expect the disk space problem to resolve itself magically?

The vm runs Ubuntu, the guest OS is Windows 8.

jon80 wrote:Do I need to re-configure the partitions within the virtual machine, not just expect the disk space problem to resolve itself magically?

Exactly

jon80 wrote:and since I initially selected a dynamically increasing drive

? No you didn't. VirtualBox provides no such option. Check the user manual for a description of those disk options it does provide.

The "dynamically increasing drive" is just the virtual drive file on the host. It doesn't immediately fill up to the size of the drive you chose when setting it up, but it will eventually. It won't go over the original set-up size.

Pretend that you set up a 100GB dynamic drive. Right after you first make the drive file, it's very tiny. The one I just made as a test is only 84KB (kilobytes) to start. Once you install the OS and programs and data, the dynamic file gets larger. Within the guest the OS will see a 100GB drive, but the dynamic file might not actually get to 100GB for a while. Eventually it will. But it will never get over 100GB either in the guest or on the host, because that's the size you started with.

Mpack's CloneVDI tool can make the dynamic disk file's size limit larger, and if there's just basic typical partitioning within the dynamic drive, the partition that the guest OS sees can get bigger, too. Otherwise you'll need to re-arrange the partitions within the guest OS, either by using the guest OS's tools, or by booting to a live-CD partition manager, like GParted.

My point is that VirtualBox does not provide a dynamically increasing [in capacity] drive option. Anyway no guest OS that I know of would support such a drive. The virtual drives which VirtualBox supports all have a fixed capacity. The only question is when that capacity gets it's corresponding storage allocation on the host. So-called "fixed" drives have the entire host storage allocation done up front at creation time, i.e. "fixed" in that case refers to how much space these occupy on the host. Dynamically allocated drives have host storage allocated on demand, as the guest OS writes to new areas of the disk. As Scottgus says, they typically start out very small, grow quickly for a while, and then level off at some size which depends on how the VM is used, but always less than or equal to their declared capacity.

In neither case can a drive store more than the capacity you chose at creation time.

Hi there,
I am a new user of Virtual Box and I see this "issue" of dynamic disk space has caught out many people for many years.
I have also just been caught by the concept of "dynamic" and I also made (the incorrect) assumption that Virtual Box would allow my "available disk space" in my guest OS to be adjusted when it was required!

I see there were lots of suggestions made in the MAC OS X area as to different wording for the set up screen as far back as 2012 and here we are in 2014 and I still got caught!

One of the suggestions was to ask for the maximum size first. I think this is a good proposal. May I further propose some different wording which I hope will be more easily understood by non technical people or most people who "don't read the manual".
I do not know if my wording is "technically correct" (please feel free to change it) but maybe it will help simple users (like myself) to better understand the choices we make during setup?

Proposed maximum size allocation wording:
Your guest OS needs to know the overall size of the virtual disk drive available to it.
You may have a 1 TB (use actual size) drive in this PC but you need to tell Virtual Box how much of that space will be seen as "Drive C:" by your guest OS.
If you allocate 50 GB then your guest OS will ONLY have a "C: drive capacity" of 50 GB.
The capacity you allocate here cannot be exceeded.

Once the user has made this selection then the second screen can completely avoid the use of the word "dynamic" by saying something like:

Proposed "dynamic file" wording:
Virtual Box can reserve the full (selected capacity) now so that your host OS will show the full (selected capacity) as "used". Adding files in your guest OS will not affect the "used space" in your host OS since you will have already "reserved" the full (selected capacity).
Alternately, you can set it to only use up space as you go along. The free space in both the host and guest OS will decrease as you add files in your guest OS till you reach (selected capacity).

Now have a tick box for: Reserve the full (selected capacity) now:

How about it?

ConDev wrote: May I further propose some different wording which I hope will be more easily understood by non technical people or most people who "don't read the manual".

I don't really see how a change in user manual wording will help people who refuse to read it.

In fact the user manual wording in section 5.2. was changed a couple of years ago, and the incidence of this misunderstanding dropped to almost nothing because of it: the question used to be a daily occurrence. So I would say we no longer have a problem. The only people caught now are those who simply haven't read the manual, and at best have been reading some ancient blog posts of... uncertain provenance.

If you want to know how VirtualBox is supposed to work, read the user manual. No other source of information means anything, and on this subject I believe the user manual is already very clear.