Achieving method of high-performance elastic-capacity virtual machine disk

The invention relates to an achieving method of a high-performance elastic-capacity virtual machine disk. The achieving method is characterized by being achieved according to a sparse file mechanism, a logical volume management mechanism and a virtual machine disk aligning principle. The achieving method comprises the steps of (1) adopting the sparse file mechanism to achieve the elastic-capacity virtual machine disk, (2) adopting the logical volume management (LVM) mechanism to achieve on-line capacity expansion of a disk space, (3) adopting the virtual machine disk aligning principle. By means of the achieving method, at least more than 50% of memory space can be greatly saved in a cloud computing environment. In addition, the input-output (IO) performance of the virtual machine disk reaches to more than 90% of the IO performance of a physical file system.