Patent ID: 8234471

Claim:
A remote copy system comprising: a first storage system having a first logical volume accompanied with a first plurality of disk drives in the first storage system; a second storage system having a second logical volume, which is a virtual volume not accompanied with a second plurality of disk drives in the second storage system, the virtual volume configuring a first remote copy pair with the first logical volume; and a third storage system having a third logical volume accompanied with a third plurality of disk drives in the third storage system, the third logical volume configuring a second remote copy pair with the virtual volume and storing a copied data of data stored in the first logical volume, wherein, if the first storage system receives a write data sent from a host computer to the first logical volume, the first storage system stores the write data in the first plurality of disk drives and sends the write data to the virtual volume in the second storage system according to a synchronous remote copy procedure, wherein, if the second storage system receives the write data sent from the first storage system to the virtual volume, the second storage system transfers the write data to the third logical volume in the third storage system according to an asynchronous remote copy procedure, and wherein, if the third storage system receives the write data transferred from the second storage system to the third logical volume, the third storage system stores the write data in the third plurality of disk drives.