Patent ID: 8645653
Filing Date: 2014-02-04
Classification: G06F

Abstract:
1. A data migration system, comprising: a first storage system; a second storage system coupled to the first storage system; and a host system including a host computer coupled to the first and second storage systems, wherein the first storage system comprises: wherein the first thin provisioning information is information containing information representing which first physical area is assigned to each virtual area of the first lower level logical volume, wherein, upon receiving a write request designating the first upper level logical volume, the first storage system assigns the first physical area from the first pool to a virtual area of a write destination in the first lower level logical volume of the first upper level logical volume, writes write target data into the first physical area, and updates the first thin provisioning information, wherein the second storage system comprises: wherein (A) the second storage system maps the first upper level logical volume to the second lower level logical volume according to storage virtualization technology, wherein (B) the host system switches an access path from the host computer from an access path to the first upper level logical volume to an access path to the second upper level logical volume, and, if the second storage system thereby receives an access request designating the second upper level logical volume from the host computer, access according to the access request is made to the first upper level logical volume via the second lower level logical volume, wherein (C) the second storage system acquires information contained in the first thin provisioning information, wherein (D) the second storage system executes copy processing of migrating data from the first upper level logical volume to the second upper level logical volume and copying the data from the second upper level logical volume to the third lower level logical volume through the third upper level logical volume, wherein (E) the second storage system, after completing the copy processing, associates the third lower level logical volume with the second upper level logical volume in substitute for the second lower level logical volume, wherein the second storage system receives a write request designating the second upper level logical volume from the host computer even during the copy processing, and, upon receiving the write request designating the second upper level logical volume from the host computer during the copy processing, transfers the write request designating the first upper level logical volume to the first storage system, wherein, in the copy processing, a virtual area to which the first physical area is assigned is specified based on the information acquired at (C) above, data in the first physical area that is assigned to the virtual area is migrated, and data regarding a virtual area to which the first physical area is not assigned is not migrated, and wherein the specified virtual area is a virtual area to which data has not yet been migrated even once in the copy processing, or a virtual area that is newly designated, after the migration of data, as a write destination of data by the host computer through the second upper level logical volume.