Patent ID: 8880810

Claim:
A storage system comprising: a first storage apparatus; and a second storage apparatus, wherein: the first storage apparatus comprises a capacity pool that is partitioned into multiple pool pages and includes a storage area of an external logical volume provided by at least one storage apparatus, the second storage apparatus provides a first virtual volume which is a virtual logical volume comprising multiple first virtual areas, in a case of receiving a write request from the computer to a virtual area in the first virtual volume to which a page is not allocated, the second storage apparatus sends the first storage apparatus an allocation request to allocate an unallocated pool page of the external logical volume to the virtual area in the first virtual volume in the second storage apparatus, an authority to allocate the unallocated pool page of the external logical volume is assigned to the first storage apparatus, and the second storage apparatus sends write data to the at least one storage apparatus providing the external logical volume.