Data backup method, apparatus, and system

A data backup method performed by a file server, comprising:

• receiving, from a backup server, a change information obtaining request requesting for change information of data in the file server;
• determining the change information of the data in the file server;
• returning a record of a data change between a second snapshot and a first snapshot to the backup server, wherein the first snapshot is created before the second snapshot, the data change record is used to record information about a data block corresponding to the change between the second snapshot and the first snapshot, and the data change record includes identification information of the changed data block;
• receiving a data obtaining request sent by the backup server, wherein the data obtaining request includes identification information of a to-be-obtained data block;
• and
• returning, to the backup server, data in the data block identified by the identification information of the data block.

A backup server comprising:

• a network interface for accessing a network;
• a memory storing executable instructions;
• a processor configured to execute the executable instructions to:
• after a data backup operation is triggered, send a change information obtaining request to a file server to request for change information of data in the file server;
• receive from the file server, a record of a data change between a second snapshot and a first snapshot taken before the second snapshot, wherein the data change record records information about a data block corresponding to the change between the second snapshot and the first snapshot, and the data change record includes identification information of the data block corresponding to the changed data;
• obtain, from the file server based on the data change record, data in the data block identified by the identification information of the data block;
• store the obtained data in a backup storage device;
• and
• establish a data mapping relationship for this backup, where the data mapping relationship includes identification information of all data blocks in the second snapshot, storage locations of all the data blocks in the second snapshot in the backup storage device, and a snapshot identifier of the second snapshot.

A file server comprising:

• a network interface for accessing a network;
• a memory storing executable instructions;
• and
• a processorconfigured to execute the executable instructions to:
• receive, from a backup server, a change information obtaining request requesting for change information of data in the file server;
• determine the change information of the data in the file server;
• return a record of a data change between a second snapshot and a first snapshot to the backup server, wherein the first snapshot is created before the second snapshot, the data change record is used to record information about a data block corresponding to the change between the second snapshot and the first snapshot, and the data change record includes identification information of the changed data block;
• receive a data obtaining request sent by the backup server, wherein the data obtaining request includes identification information of a to-be-obtained data block;
• and
• return, to the backup server, data in the data block identified by the identification information of the data block.