Storage system which realizes asynchronous remote copy using cache memory composed of flash memory, and control method thereof

A storage system comprising:

• a first storage apparatus including a first processor, a first memory device providing storage area for a primary logical volume, and a first flash package which has a plurality of first flash memory chips and a first package processor and temporarily stores data to be wrote to the primary logical volume;
• and
• a second storage apparatus including a second processor, and a second memory device providing storage are for a secondary logical volume, and receiving journal data corresponding to write data to the primary logical volume and update information, and reflecting the journal data to the secondary logical volume according to the update information;
• wherein when the first storage apparatus receives a write command which requests to write a first write data to the primary volume,
• the first package processor in the flash package receives the first write data transferred by control of the first processor, allocates first physical area in the first flash memory chips to first cache logical area for write data managed by the first flash package, and writes the first write data to the allocated first physical area,
• the first package processor in the flash package receives first journal data creation request corresponding to the first write data from the first processor, and allocates the first physical area which stores the first write data to second cache logical area for journal data managed by the first flash package.