The embodiment of the invention discloses a
system mirror image file updating method of a
virtual machine. The
system mirror image file updating method comprises the steps that when a
virtual machine creating request is received, a target computing
resource pool is selected from multiple computing resource pools, and a third
virtual machine is created according to the target computing
resource pool; on the condition that a
system mirror image file of the third virtual
machine is updated, data of a preset first system mother volume and incremental data of the system mirror image file are obtained; a new system mirror image file is synthesized based on the incremental data of the system mirror image file and the data of the first system mother volume; a second system mother volume of the third virtual
machine is created in the target computing
resource pool, and the new system mirror image file is stored in the second system mother volume; a second snapshot photo is generated according to the second system mother volume; a third linkage clone volume is created according to the second snapshot photo, and the third virtual
machine is started according to the third linkage clone volume. The embodiment of the invention further discloses a
cloud data center and a system. By the adoption of the system mirror image file updating method, the system mirror image file updating time is shortened, and storage space is reduced.