Abstract: A virtual machine backup method, performed by a first host, includes: capturing a request to write data from a virtual machine to a hard disk image file, wherein the request includes written data and input and output location information, copying the written data to a temporary storage area, calculating a first key of the written data, storing the first key, the input and output location information into a first resource location structure, pausing an operation of the virtual machine and generating a second resource location structure according to the first resource location structure, the first key and a second key, and outputting a backup data set to a second host according to the second resource location structure, wherein the backup data set includes the second resource location structure and only one of existing data and the written data when the first key and the second key are the same.

Abstract: A computing device is provided, which includes a volatile memory, a non-volatile memory, and a processor. A processor is configured to execute a main virtual machine for: during a detection period, detecting a cold area used by the main virtual machine from the volatile memory and the non-volatile memory; transmitting first data belonging to the cold area in the volatile memory and the non-volatile memory to a backup device; when determining that a first transmission condition is satisfied, transmitting a second data used by the main virtual machine in the volatile memory and the non-volatile memory to the backup device; and when determining that an abnormal event has occurred, notifying the abnormal event to the backup device, so as to execute a backup virtual machine in the backup device according to the first data and the second data.

Abstract: The present invention includes a main device and a backup device. A first backup system element of the main device is used to determine whether a first estimated time is less than a second estimated time. The first estimated time is a time period for directly transmitting pending data. The second estimated time is a time period for transmitting the pending data after the pending data is compressed by a current compression algorithm. If yes, the first backup system element directly transmits the pending data to a second backup system element of the backup device. If not, the first backup system element compresses the pending data by the current compression algorithm, updates the pending data and the current compression algorithm, and re-determines whether the first estimated time is less than the second estimated time. The present invention improves availability of data backup when a network bandwidth is poor.