Method and apparatus for data backup in storage system

A storage system comprising:

• a source device;
• and
• a backup-end device;
• wherein data of an nth snapshot Sn is stored in the source device, and the data of the nth snapshot Sn in the source device and data of an xth snapshot Sx are stored in the backup-end device, wherein n and x are integers, and n<x;
• wherein the source device is configured to send a data recovery request to the backup-end device, wherein the data recovery request carries a version number of the snapshot Sn;
• wherein the backup-end device is configured to:
• receive and parse the data recovery request to obtain the version number of the snapshot Sn;
• determine a first data block according to the version number of the snapshot Sn and a version number of the snapshot Sx;
• determine, according to a logical address of the first data block and the version number of the snapshot Sn, a second data block recorded in the snapshot Sn;
• perform a logical operation on the first data block and the second data block to obtain a third data block;
• compress the third data block to obtain a fourth data block;
• and
• send, to the source device, a data packet that carries the fourth data block and the logical address of the first data block, wherein the first data block is a data block that is recorded in the snapshot Sx backed up by the backup-end device and that is written by the source device after the nth snapshot Sn, and the first data block is a modified block of the second data block, wherein the logical operation is an exclusive-OR operation or an exclusive-NOR operation;
• and
• wherein the source device is further configured to:
• receive and parse the data packet to obtain the fourth data block and the logical address of the first data block;
• determine, according to the logical address of the first data block, the second data block recorded in the snapshot Sn;
• decompress the fourth data block to obtain the third data block;
• perform the logical operation on the third data block and the second data block to obtain the first data block;
• and
• write the first data block to the logical address of the first data block.

A storage device, comprising:

• an interface;
• and
• a processor coupled to communicate with the interface over a bus;
• wherein the storage device is configured to communicate with a backup-end device, wherein the backup-end device and the storage device are both configured to store data of an nth snapshot Sn, wherein n is an integer;
• wherein the processor is configured to:
• determine a first data block that is written to the storage device after the nth snapshot Sn;
• determine, according to a logical address of the first data block, a second data block recorded in the nth snapshot Sn, wherein the first data block is a modified block of the second data block;
• perform a logical operation on the first data block and the second data block to obtain a third data block, wherein the logical operation is an exclusive-OR operation or an exclusive-NOR operation;
• and
• compress the third data block to obtain a fourth data block;
• and
• wherein the interface is configured to send, to the backup-end device, a data packet that carries the fourth data block, the logical address of the first data block, and a version number of the nth snapshot Sn.

A storage device, comprising:

• an interface;
• and
• a processor coupled to communicate with the interface over a bus;
• wherein the storage device is configured to communicate with a source device, wherein the source device and the storage device are both configured to store data of an nth snapshot Sn, wherein n is an integer;
• wherein the interface is configured to receive and parse a data packet sent by the source device, to obtain a fourth data block, a logical address of a first data block, and a version number of the nth snapshot Snand
• wherein the processor is configured to:
• determine, according to the logical address of the first data block and the version number of the nth snapshot Sn, a second data block recorded in the snapshot Sn, wherein the first data block is a data block written by the source device after the nth snapshot Sn, and the first data block is a modified block of the second data block;
• decompress the fourth data block to obtain a third data block;
• perform a logical operation on the third data block and the second data block to obtain the first data block, wherein the logical operation is an exclusive-OR operation or an exclusive-NOR operation;
• and
• write the first data block to the logical address of the first data block.