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Public OTC KVM Windows images published between January and April 2019 contains KVM driver package This package contains a storage driver, which does not recognize expanded disks. It is recommended updating drivers to current version (>=

Error Description

KVM based Windows servers lack the ability to online resize the disks. After expanding disk capacity on OTC Console, the operating system will not recognize the new disk space. If affected disk is a data disk, it has to be detached and re-attached. If affected disk is a system disk (boot disk), the ECS has to be restarted. Cause of the issue is driver Red Hat VirtIO SCSI controller version

The newer driver version resolves this issue.

Driver Update Procedure

Do not do this update without backup. The storage driver is necessary for booting the system. Mistakes in update procedure may destroy the system.

Download current KVM driver iso file:

  1. Create snapshot of the system disk

  2. Mount the ISO

  3. Execute "Setup.exe" - There is no progress bar, suddenly a dialog box will pop up after installation is finished.

  4. Click OK to let reboot, or cancel to reboot later

  5. After reboot, remount the ISO

  6. Open Device Manager

  7. Navigate to "Storage controllers"

  8. Right-click on "Red Hat VirtIO SCSI controller" - Update Driver Software

  9. Click "Browse my computer for driver software"

  10. Click on "Browse..." button

  11. Select \upgrade\--OS--\drivers\vioscsi\ folder from mounted iso (for Windows Server 2019 choose windows 2016_64 as --OS--)

  12. Ok, Next

  13. Repeat step 8. to 12. for every Red Hat VirtIO controller

  14. Reboot server