virtualbox.org

I have a Mid 2010 Mac Pro (6-core, 8GB of RAM, 3.33 GHz model) running Mac OS X 10.6.8 and VirtualBox 4.1.10.

Today I added a CentOS 6.2 x86_64 appliance and set it to use 4 CPUs and 2 GB of RAM, as I do with my other VMs (Solaris 11/Windows 8 CP).

I wanted to test being able to create Linux EXT3 filesystems in the VM environment, so I stuck in a Corsair 32 GB USB stick.

I created a USB Device Filter for it and it is seen in VBox - if I go to the USB icon in the pull-down menu I see it checked (and it's not greyed out).

It was successfully taking the device from OS X as the USB stick wasn't mounted in OS X when I plugged it in.

But the OS wasn't seeing it at all. At one point I did a cat /proc/bus/usb/devices and that command wedged.

I couldn't seem to get it to work. After some Googling around, I found a VirtualBox on iMac post [newbie alert - I can't post URLs yet] by Rice University's Anhei Shu where he said that he couldn't see his USB device (in a Ubuntu 11 guest VM) until/unless he set the VM to only use 1 CPU.

So I shut down the VM and changed the settings to use 1 CPU instead of 4, restarted the VM and - voila! - USB stick seen, everything works now. Looks like Anhei was right?

So, I have a work-around (thankfully) but I don't really want to run the VM with 1 CPU in practice, or have to remember to restart with 1 VCPU every time I want to do something with a USB device.

Is this a Known Problem™?

VMs often run slower with multiple CPUs, I assume the problem derives from that. Why do you need multiple CPUs? Do you have apps that need lots of truly parallel threads going?

mpack wrote:Why do you need multiple CPUs?

I think that while it doesn't make his guest OS run any faster or better, it does make it seem more studly that it's running on four cores (leaving only two for the host) than if it was running on one wimpy core. In other words, bragging rights.

Same problem. with 4.1.8 usb works fine - with 4.1.10 on same machine, with same usb device it will not work. so i installed 4.1.8 again.
and i am afraid to install 4.1.12 ...

perolin wrote:and i am afraid to install 4.1.12

If you are afraid to test the latest version then how can you get bugfixes?

This is still seems to be a problem in 4.1.12

Oh god I'm so thankful to Google for making me stumble upon this thread. I also got this error, in 4.1.12 version. This is my hardware setup, if any of developers will be interested:

Hardware Overview:

Model Name: MacBook Pro
Model Identifier: MacBookPro8,2
Processor Name: Intel Core i7
Processor Speed: 2 GHz
Number of Processors: 1
Total Number of Cores: 4
L2 Cache (per Core): 256 KB
L3 Cache: 6 MB
Memory: 8 GB
Boot ROM Version: MBP81.0047.B27