Patent ID: 8312237

Claim:
A method of providing access to data, the method comprising: providing a storage grid which includes a source chain of storage nodes and a target chain of storage nodes, the source chain including a primary source node and a secondary source node which operates as a data mirror of the primary source node, and the target chain including a primary target node and a secondary target node which operates as a data mirror of the primary target node; initially storing data on the source chain, the primary source node of the source chain maintaining a primary source copy of the data, and the secondary source node of the source chain maintaining a secondary source copy of the data; and relocating the data from the source chain to the target chain, the primary target node of the target chain maintaining a primary target copy of the data, and the secondary target node of the target chain maintaining a secondary target copy of the data, access to the data being continuously provided from the storage grid to an external device before, during, and after relocation of the data from the source chain to the target chain.