I am trying to install Ubuntu 10.04 LTS Server on Server 2008 R2 Hyper-V. I have setup a hard drive that is 400GB. Yet every time I try to install it only recognizes it as a 136gb drive.

I have tried the following:


Fixed vs Dynamic disk

Diff SCSI and IDE channels

Any ideas?


  • 136GB (127GiB) is the pre-ATA/100 interface limit if that helps anyone. – Rob Olmos Sep 4 '10 at 1:50

I had the same problem as this and found the solution here: http://fawzi.wordpress.com/2010/05/03/ubuntu-server-10-4-in-hyper-v/

Although this article is about the synthetic NIC and how to use that instead of the legacy driver it also worked for the larger drive. I created a small VHD and added it to the IDE Controller as the root partition to boot from as /dev/hda1 and then created a big VHD and added it to the SCSI Controller. When the drive was mounted it showed the full space available in fdisk.

If the hv_ modules are not loaded then I could not see the drive as a device at all.

NOTE: If you follow the above website instructions to use Synthetic NIC then you'll also need this article: http://ubuntuforums.org/showthread.php?p=9876653

As the synthetic NIC didn't work for me until I did the above.

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I haven't used Hyper-V but try something more related to the virtual BIOS or controller settings like 48-bit LBA.

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  • All the BIOS settings seem to work fine. Also with CentOS the hard drive size shows up fine. So it is only Ubuntu. Any ideas? – Physikal Sep 9 '10 at 23:27
  • It's also Debian – Christian Oct 11 '10 at 8:51

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