Storage system and storage control method

A storage control method comprising:

• when copy target data, which is data to be copied, is copied in a volume or between volumes among one or more volumes to which two or more volume addresses, which are two or more logical addresses, belong,
• (A) determining whether a copy destination physical drive, which is a physical drive corresponding to a copy destination volume address, is identical to a copy source physical drive which is a destination physical drive corresponding to a copy source volume address;
• and
• (B) shifting a storage position of the copy target data such that the copy destination physical drive becomes a physical drive identical to the copy source physical drive if a determination result of (A) is false,
• wherein
• the copy target data is data to be copied from a copy source area according to the copy source volume address and a copy amount which is an amount of the copy target data to a copy destination area according to the copy destination volume address and the copy amount,
• the copy source physical drive is a physical drive storing a head data set,
• the head data set is a data set stored at a head of the copy source area,
• the copy destination physical drive is a physical drive to which the head data set is copied,
• the plurality of physical drives provide a plurality of drive areas constituting a redundant array of independent (or inexpensive) disks (RAID) area,
• each of the plurality of drive areas is a logical storage area constituted by two or more strips,
• the RAID area is constituted by a plurality of stripes,
• each of the plurality of stripes is constituted by a plurality of strips provided in each of the plurality of drive areas,
• each of the copy destination area and the copy source area is an area in the RAID area,
• one or more data sets are stored in one or more strips included in the copy source area, respectively,
• the one or more data sets include one or more user data sets out of one or more user data sets constituting the copy target data,
• two or more drive addresses, which are two or more logical addresses, belong to each of the plurality of drive areas,
• a RAID level of the RAID area is a RAID level that requires at least one parity per stripe, and
• in (B), for each of one or more copy destination stripes, which are one or more stripes relating to the copy destination area, the storage controller
• (b1) determines whether a copy destination range in the copy destination stripe is the entire copy destination stripe,
• (b2) transmits a copy command designating a copy source drive address and a copy destination drive address to each of the plurality of physical drives without processing for calculating a parity to be stored in the copy destination stripe if a determination result of (b1) is true,
• a copy source drive address being a drive address of a copy source strip and the copy source strip being a drive address of a strip provided by a physical drive in a copy source stripe corresponding to the copy destination stripe, for each of the plurality of physical drives, and
• a copy destination drive address being a drive address of a copy destination strip and the copy destination strip being a drive address of a strip provided by a physical drive in the copy destination stripe, for each of the plurality of physical drives, and
• (b3) performs parity processing which is processing for calculating a parity to be stored in the copy destination stripe if the determination result of (b1) is false.

A computer program that causes a computer to execute:

• when copy target data, which is data to be copied, is copied in a volume or between volumes among one or more volumes to which two or more volume addresses, which are two or more logical addresses, belong,
• (A) determining whether a copy destination physical drive, which is a physical drive corresponding to a copy destination volume address, is identical to a copy source physical drive which is a destination physical drive corresponding to a copy source volume address;
• and
• (B) shifting a storage position of the copy target data such that the copy destination physical drive becomes a physical drive identical to the copy source physical drive if a determination result of (A) is false,
• wherein
• the copy target data is data to be copied from a copy source area according to the copy source volume address and a copy amount which is an amount of the copy target data to a copy destination area according to the copy destination volume address and the copy amount,
• the copy source physical drive is a physical drive storing a head data set,
• the head data set is a data set stored at a head of the copy source area,
• the copy destination physical drive is a physical drive to which the head data set is copied,
• the plurality of physical drives provide a plurality of drive areas constituting a redundant array of independent (or inexpensive) disks (RAID) area,
• each of the plurality of drive areas is a logical storage area constituted by two or more strips,
• the RAID area is constituted by a plurality of stripes,
• each of the plurality of stripes is constituted by a plurality of strips provided in each of the plurality of drive areas,
• each of the copy destination area and the copy source area is an area in the RAID area,
• one or more data sets are stored in one or more strips included in the copy source area, respectively,
• the one or more data sets include one or more user data sets out of one or more user data sets constituting the copy target data,
• two or more drive addresses, which are two or more logical addresses, belong to each of the plurality of drive areas,
• a RAID level of the RAID area is a RAID level that requires at least one parity per stripe, and
• in (B), for each of one or more copy destination stripes, which are one or more stripes relating to the copy destination area, the storage controller
• (b1) determines whether a copy destination range in the copy destination stripe is the entire copy destination stripe,
• (b2) transmits a copy command designating a copy source drive address and a copy destination drive address to each of the plurality of physical drives without processing for calculating a parity to be stored in the copy destination stripe if a determination result of (b1) is true,
• a copy source drive address being a drive address of a copy source strip and the copy source strip being a drive address of a strip provided by a physical drive in a copy source stripe corresponding to the copy destination stripe, for each of the plurality of physical drives, and
• a copy destination drive address being a drive address of a copy destination strip and the copy destination strip being a drive address of a strip provided by a physical drive in the copy destination stripe, for each of the plurality of physical drives, and
• (b3) performs parity processing which is processing for calculating a parity to be stored in the copy destination stripe if the determination result of (b1) is false.