Patent ID: 9594583
Date: 2017-03-14
CPC Classifications: G06F

Claim:
1. A method, comprising: receiving a write request comprising data from a guest operating system of a virtual machine, wherein the write request is directed to a sector of a virtual disk associated with the virtual machine, the virtual disk comprising a base image and an overlay image, the base image comprising a current version of the virtual disk and the overlay image comprising a snapshot of the base image prior to the current version; determining, by a processing device, whether a corresponding sector in the overlay image of the virtual disk is marked as present; responsive to the corresponding sector in the overlay image not being marked as present, copying data from the sector in the base image to the corresponding sector in the overlay image and marking the corresponding sector in the overlay image as present prior to writing the data from the guest operating system of the virtual machine to the sector in the base image of the virtual disk; and responsive to the corresponding sector in the overlay image being marked as present, writing, by the processing device, the data from the guest operating system of the virtual machine to the sector in the base image of the virtual disk without copying data from the sector in the base image to the corresponding sector in the overlay image.