When creating a new fixed size VM in VirtualBox even though my memory usage, my CPU usage and my I/O usage in "System Monitor" stay at their normal levels, my entire machine freezes and becomes unresponsive until the VM has been fully created (which takes around 5 minutes). Why is this? And if no extra CPU, memory or I/O usage is being used, then why is the entire machine becoming unresponsive? Is it just that there is a problem with System Monitor not displaying the correct information, or something else slowing the machine down which is not to do with CPU, memory or I/O usage?

I have installed VirtualBox from the official repository by adding:

deb http://download.virtualbox.org/virtualbox/debian wily contrib

To my sources file, running:

wget -q https://www.virtualbox.org/download/oracle_vbox.asc -O- | sudo apt-key add -

And then installing the virtualbox-5.0 package, version 5.0.14 r105127. Though the issue was present when I installed VirtualBox from the official Ubuntu repositories, and also when I installed it from the .deb from the website.

My CPU type is i3.

And just to say this again to make it very clear, this occurs during the time that the drive is actually being created, once it has been created, there is no problem installing the OS on it, but it is during the creation, not usage. So it happens when I press the "Create" button:

enter image description here

When I ran the free command during the creation, this is one of the outputs I got (the cached size was always growing):

             total       used       free     shared    buffers     cached
Mem:       3894816    3860184      34632     341108      23680    1567908
-/+ buffers/cache:    2268596    1626220
Swap:      4038652     118476    3920176
  • 1
    Panda: freeze has long been considered a bad tag and considered meta information. Please don't keep adding it to your posts. :)
    – Seth
    Feb 2, 2016 at 23:16

1 Answer 1


The problem is with the creation of the disk image.

Creating an 8GB fixed size disk image requires writing 8GB of blanks to the disk.

I've tested this on my system and my system consistently slows down as well during the creation of a fixed size disk image; the I/O saturation resulting from the task running at full speed clutters the system visibly:


(this was the absolute peak, it sat on average at around 75 MB/s).

The solution is to be patient and to wait for the task to finish; in general changing the kernel's I/O scheduler can help in case of intensive I/O activities.

  • My system slows down (for a second) but there is a nice progress box indicating that Virtualbox is doing something. Is Ubuntu's different from Debian? Mine is 5.0.14-dfsg-1.
    – Braiam
    Feb 2, 2016 at 16:33
  • Also, OP indicates that I/O levels stay normal (at least System Monitor says so).
    – Braiam
    Feb 2, 2016 at 16:38
  • @Braiam No, it's the same on Ubuntu. I'm not sure what OP actually monitored because 1) System Monitor doesn't report I/O activity 2) I monitored I/O activity on my system during the creation of a bogus fixed size disk image and I/O sat on average at around 75 MB/s during the whole task (from other tests I know that my disk's I/O speed caps at around 80 MB/s). All in all I think the whole problem has been simply that OP hadn't provided reliable information about his I/O activity.
    – kos
    Feb 2, 2016 at 17:02
  • Ok, I've tested the I/O usage again, and it seems that some error was made when I previously checked, because it does sky rocket...
    – user364819
    Feb 2, 2016 at 18:53

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