Patent ID: 9298734
Filing Date: 2016-03-29
CPC Classification: G06F

Claim Text:
1. A storage system having storage subsystems coupled to one or more client computers, and sharing and storing files to be accessed the storage system comprising: a first storage subsystem, and a second storage subsystem newly performing file sharing instead of the first storage subsystem; wherein a first data migration method (PUSH type) where the first storage subsystem writes files in the first storage subsystem to the second storage subsystem to perform data migration, and a second data migration method (PULL type) where the second storage subsystem reads the files in the first storage subsystem and stores the read data in the second storage subsystem to perform data migration are switched selectively to perform data migration of files from the first storage subsystem to the second storage subsystem, and wherein the first storage subsystem: determines an access characteristics based on an access frequency and an update frequency of each file in the first storage subsystem; classifies the files in the first storage subsystem into a first file group having a high possibility of being accessed and a second file group having a low possibility of being accessed; when the first data migration method (PUSH type) is selected to perform data migration, files of the second file group are subjected to data migration to the second storage subsystem, and after completing data migration, files of the first file group are subjected to data migration to the second storage subsystem; when the second data migration method (PULL type) is selected to perform data migration, the files of the first file group are subjected to data migration to the second storage subsystem, and after completing data migration, files of the second file group are subjected to data migration to the second storage subsystem; and the files of the first file group are subjected to data migration from files having smaller file sizes, and the files of the second file group are subjected to data migration from files having greater file sizes.