Patent ID: 7934068

Claim:
A storage apparatus comprising: a drive unit in which at least one logical unit is formed; and a controller unit configured to access the at least one logical unit by controlling the drive unit in accordance with an access request sent from a host apparatus, wherein the controller unit comprises: a takeover request unit configured to issue a takeover request of the at least one logical unit to a plurality of other storage apparatuses; an external storage configuration unit configured to allocate to the at least one logical unit a logical unit formed in each of the plurality of other storage apparatuses that will accept the takeover of the at least one logical unit according to a takeover approval sent each from the plurality of other storage apparatuses in response to the takeover request sent from the takeover request unit; a data migration unit configured to migrate data in the at least one logical unit to a logical unit formed in each of the plurality of other storage apparatuses allocated with the external storage configuration unit; and a path switch request unit configured to issue a path switch request such that an access request sent from the host apparatus is given to at least one of the plurality of other storage apparatuses after the migration of the data by the data migration unit is complete.