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I have (portable) Virtualbox installed on a USB key running on a 64-bit Windows 7 host. I installed 32 bit Ubuntu 10.04 as a guest OS.

During spikes in processor usage on the guest OS (based on looking at top), the Ubuntu virtual box freezes up for 5-10 seconds. The guest becomes unresponsive with the VirtualBox window showing as "not responding". There seems to maybe be a correlation between this behavior and network accesses.

I've experimented with the number of CPUs allocated to the virtual box, added and removed RAM, and adding video memory -- all to no avail. I have not attempted disabling or changing the processor level virtualization (VT-x).

I'm wondering if there's anything particular about Ubuntu 10.4 that might be impacting this? Should I have installed 64-bit Ubuntu (or should it matter!?). Is there a VirtualBox setting I'm missing that would improve my experience?

Any help is appreciated.

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I have never used Virtualbox on a Windows host, but 10.04 works fine on an Ubuntu host. Also it being a portable app might be something as well. – NightwishFan Sep 28 '10 at 5:59
up vote 3 down vote accepted

I suppose that running VirtualBox on a USB key is the problem. USB keys have slower write times than harddrives. So what happens is that the Ubuntu VM writes data to it's disk (which is also stored on the USB key I suppose) and the data can't be written fast enough on the key so the VM hangs.

If you copy the Ubuntu hard disk image to your harddrive and use this one to boot Ubuntu are you experiencing the same problems?

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copying to my ssd appears to have cleared up any problems. Strange I had success with running from a USB key in the past. – Doug T. Sep 29 '10 at 2:16
Some USB keys have slower write speed. Maby you can reduce the disk wirtes within the VM with this Tweaks (at your own risk) :… – mw88 Sep 29 '10 at 7:35
I wonder too if swap space would hinder the performance. – Doug T. Sep 29 '10 at 13:43

I'd agree that you shouldn't expect good performance from a virtualised product running on a USB device (which is presumably FAT). USB is a very slow bus to try running a hefty job like a virtualised OS through.

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