Storage system, data transfer method, and program

A data transfer method for a storage apparatus including:

• a first disk array apparatus configured with first logical volumes for storing data sent from a host system;
• a second disk array apparatus configured with second logical volumes for storing back-up data of the first logical volumes;
• and a console terminal which operates the first disk array apparatus,
• wherein the console terminal includes a setting unit for setting a priority for each first logical volumes in accordance with an external command, the method comprising:
• a step whereby the first disk array apparatus, when received a write command to one of the first logical volumes from the host system, sets a highest priority as a volume priority of the one of the first logical volumes in a case where a synchronization transfer mode is set to the first disk array apparatus,
• a step whereby the first disk array apparatus sets a priority set by the console terminal as the volume priority of the one of the first logical volumes in a case where the synchronization transfer mode is not set to the first disk array apparatus, and
• a step whereby the first disk array apparatus transfers the data stored in the one of the first logical volumes to one of the second logical volumes of the second disk array apparatus according to the volume priority of the one of the first logical volumes.