Disclosed is a method, a system and a serving node for data backup and restoration, in which a serving node generates a backup schedule after receiving a data backup request, uploads the schedule to a cluster public storage block, each serving node sends a copy to be backed up to a target node for consolidation; a client sends a data record in a consolidated copy to the serving node through a data writing request, generates a data distribution table according to a load balancing principle, sends the request to other serving nodes according to the table to perform a write operation, the client sends the data writing request for a next data record after the write operation, until the copy is completely restored. The backup and restoration is performed in a complex cluster network accounting for performance differences among serving nodes, data consistency, data integrity and data uniform distribution.