Method and system for creating snapshots by condition

A data management method in a storage device system having a control device connected to a computer, and a storage device connected to the control device, the data management method comprising:

• the control device receiving conditions for determining whether or not to save data stored at a certain point in time in a file from one or more files stored in the storage device;
• and
• the control device storing the conditions in the storage device system;
• wherein the control device receives from the computer a request including specification of the conditions to save data stored in the file, and the control device determines, based on the request, the file which meets conditions included in the request and for which data stored at a certain point in time in the file is to be saved;
• the control device deciding, when a write request for the one or more files is received from the computer, after receipt of the request, whether or not a file corresponding to the write request is a file meeting the conditions included in the request;
• the control device saving the data stored in the area corresponding to the write request, and then writing the data to the area specified in the write request in accordance with the write request, if a file corresponding to the write request is a file meeting the conditions included in the request;
• and
• the control device writing the data to the area corresponding to the write request in accordance with the write request, if a file corresponding to the write request is not a file meeting the conditions.