| 摘要 |
PROBLEM TO BE SOLVED: To avoid becoming unable to write due to the shortage of free space in a data storage unit, etc., and copy a chunk appropriately.SOLUTION: When a request for write to a snapshot corresponding to file data which is stored in a plurality of data servers and which is stored separately in chunks of fixed length is accepted, a master server 100 determines a data server to which a chunk that is the object of the write request is copied by copy-on-write on the basis of one or more of a free space in the data storage unit of each data server, a distance between the data server holding the chunk to be copied and each data server, and the number of chunks shared by a plurality of files in each data server. Then, the master server 100 exerts control on the determined data server so that a chunk that is the object of the write request is copied. |
