1. A data migration method comprising: creating, by a first control processor that controls a first cache memory storing first cache data cached from first storage data stored in a storage, first management information including information indicating a storage location of the first cache data on the first cache memory and information indicating whether or not the first storage data has been updated in accordance with an update of the first cache data for each block of a predetermined data size in the first cache memory, when a program that accesses the first cache data migrates to a different node, transmitting, by the first control processor, the first management information to a second control processor that controls a second cache memory capable of being accessed by the program after migration to the different node, first acquiring, by the second control processor, the first cache data from the first cache memory on the basis of the received first management information, and storing, by the second control processor, the acquired first cache data into the second cache memory, and specifying, by the second control processor, cache data corresponding to the block corresponding to the first storage data that is not updated among the stored first cache data on the basis of the received first management information, and first updating, by the second control processor, the first storage data on the basis of the specified cache data.