table 4005 is lu creation step 13004 if the determined result is true the cpu 1102 considers that the read record is not a target for the capacity trend prediction process step 13005 if the determined result is false the cpu 1102 reads the subsequent record step 13006 step 13003 and step 13004 may be performed in inverse order in addition any one of step 13003 and step 13004 may be performed fig1 shows a process flow of the lu status determination process the lu status determination process is the process that determines whether the lu is allocated to the computer or not and used by the computer or not the lu that is not allocated to the computer and the lu that is allocated to the computer but not used by the computer are not targets for the capacity trend prediction process the capacity determination program 3001 refers to the selected record of the storage device configuration information table 4003 and determines whether the connection destination i f 8003 is valid step 14001 when the connection destination i f 8003 is valid it indicates that the lu is allocated to the computer if the determined result is true the capacity determination program 3001 updates the allocation 6003 to u201c true u201d which has the records that the storage name 6001 and the lu name 6002 of the lu status management table 3003 are the same as the storage name 7001 and the lu name 7002 of.