Distributed file system

A multiplexing method executed by a distributed file system which includes a first computer node comprising a first file system, a second computer node connected to the first computer node so as to be capable of communicating therewith and comprising a second file system as a replica of the first file system, and a third computer node connected to the second computer node so as to be capable of communicating therewith and comprising a third file system as a replica of the first file system, and in which the first computer node includes an incremental data generating unit, a first storing unit and a first controlling unit, the second computer node includes a second storing unit and a second controlling unit, and the third computer node includes a third storing unit and a third controlling unit,

• the multiplexing method in the distributed file system, comprising:
• generating a set of changed blocks from a previous incremental data generation moment among blocks of the first file system as incremental data, by the incremental data generating unit of the first computer node;
• storing the incremental data generated by the incremental data generating unit into the first storing unit and transmitting to the second computer node, by the first controlling unit of the first computer node;
• wherein, in the generation of the incremental data by the incremental data generating unit, a snapshot that includes an image of the first file system is acquired for every change and addition or at regular intervals and a difference between a currently acquired snapshot and a previously acquired snapshot is calculated as the incremental data,
• storing the incremental data received from the first computer node into the second storing unit, reflecting on the second file system, and transmitting to the third computer node, by the second controlling unit of the second computer node;
• storing the incremental data received from the second computer node into the third storing unit and reflecting on the third file system, by the third controlling unit of the third computer node;
• and
• when plural incremental data received from the first computer node are accumulated in the second storing unit, before transmitting the plural incremental data to the third computer node, merging plural sets of changed blocks of the plural incremental data into merged one incremental data, and then the second controlling unit transmits the merged one incremental data, rather than each piece of the plural incremental data received from the first computer node, to the third computer node.

A computer node connected to an upstream computer node and a downstream computer node so as to be capable of communicating therewith, and including a replication file system that is a replica of a master file system, a storing unit, and a controlling unit, stored on a non-transitory computer readable recordable medium,

• wherein the controlling unit receives incremental data including a set of changed blocks from a previous incremental data generation moment among blocks of the master file system from the upstream computer node, stores into the storing unit, reflects on the replication file system, transmits to the downstream computer node and, when plural incremental data received from the upstream computer node are accumulated in the storing unit, before transmitting the plural incremental data to the downstream computer node, the controlling unit merges plural sets of changed blocks of the plural incremental data into merged one incremental data and then the controlling unit transmits the merged one incremental data, rather than each piece of the plural incremental data received from the upstream computer node, to the downstream computer node,
• wherein a snapshot is created that includes an image of the upstream file system for every change and addition or at regular intervals, and calculates a difference between a currently acquired snapshot and a previously acquired snapshot as the incremental data.