Storage system

A storage system transferring user data within the system, comprising:

• a first transfer engine;
• a second transfer engine;
• a first storage device;
• a second storage device;
• a processor;
• and
• a transfer sequencer which is a device different from the processor,
• wherein:
• the processor creates transfer sequence information for indicating sequential order of transfers of user data;
• the transfer sequence information includes identification information on a destination and a source, storage address information of the user data at the destination and the source, and information indicating sequential order of transfers of the user data;
• the transfer sequencer receives the transfer sequence information created by the processor and controls the first and the second transfer engines in accordance with the transfer sequence information;
• the first transfer engine transfers received user data to the first storage device in accordance with an instruction from the transfer sequencer;
• the first storage device stores the transferred user data;
• the second transfer engine transfers the user data in the first storage device to the second storage device in accordance with an instruction of the transfer sequencer;
• and
• the second storage device stores the transferred user data.