In one general aspect, a data access method is disclosed that includes directing data block write requests from different clients to different data storage servers based on a map. Data blocks referenced in the data block write requests are stored in the data storage servers. Data from the data write requests are also relayed to a parity server, and parity information is derived and stored for the blocks. This method can reduce the need for inter-server communication, and can be scaled across an arbitrary number of servers. It can also employ parity load distribution to improve the performance of file transfers.