Disk array apparatus and data backup method used therein

A disk array apparatus including a disk array which is made up of a plurality of disk drives, has a redundancy disk configuration, and is regarded as one logical disk drive by a host computer, said disk array apparatus comprising:

• an address translation table including address translation information, said address translation information being used for translating a logical address the host computer uses for specifying a valid logical block into a physical address indicating where in the disk array the logical block is stored;
• means for making a copy of the address translation table before starting a backup operation, which backs up data stored in the disk array in a mass storage device;
• means for sorting the address translation information included in the copy of the address translation table in an order determined by physical addresses included in the address translation information;
• means for reading from the disk array a physical stripe determined by the order of the physical addresses, in accordance with an address translation table in which the address translation information is sorted;
• means for managing the physical stripe read by the reading means, as a first physical stripe of physically consecutive physical stripes ruled out from segment cleaning;
• and
• data block writing means for writing in the mass storage device a data block corresponding to a valid logical address included in the physical stripe read by the reading means.

A computer system equipped with:

• a host computer including a main memory;
• a disk array apparatus including a disk array which is made up of a plurality of disk drives, has a redundancy disk configuration, and is regarded as one logical disk drive by a host computer;
• and a mass storage device in which data of the disk array is backed up, said computer system comprising:
• an address translation table including address translation information, said address translation information being used for translating a logical address the host computer uses for specifying a valid logical block into a physical address indicating where in the disk array the logical block is stored, said address translation table being included in the disk array apparatus;
• means for generating a copy of the address translation table in response to a backup start request issued by the host computer and keeping the copy in the main memory, said generating means being included in the disk array apparatus;
• means for searching for a valid logical address in accordance with the copy of the address translation table, said searching means being included in the host computer;
• means for reading from the disk array a physical stripe including a data block whose physical address corresponds to the valid logical address searched for by the searching means, said reading means being included in the host computer;
• and
• data block writing means for writing in the mass storage device a data block corresponding to a valid logical address included in the physical stripe read by the reading means, said data block writing means being included in the host computer.

A method for backing up data in a mass storage device from a disk array which is made up of a plurality of disk drives, has a redundancy disk configuration, and is regarded as one logical disk drive by a host computer, said method comprising:

• making a copy of an address translation table including address translation information before starting a backup operation, which backs up the data stored in the disk array in the mass storage device, said address translation information being used for translating a logical address the host computer uses for specifying a valid logical block into a physical address indicating where in the disk array the logical block is stored;
• searching for a valid logical address in accordance with the copy of the address translation table;
• reading from the disk array a physical stripe including a data block whose physical address corresponds to the valid logical address that is searched for;
• and
• writing in the mass storage device a data block corresponding to a valid logical address included in the read physical stripe.

A method for backing up data in a mass storage device from a disk array which is made up of a plurality of disk drives, has a redundancy disk configuration, and is regarded as one logical disk drive by a host computer, said method comprising:

• making a copy of an address translation table including address translation information before starting a backup operation, which backs up the data stored in the disk array in the mass storage device, said address translation information being used for translating a logical address the host computer uses for specifying a valid logical block into a physical address indicating where in the disk array the logical block is stored;
• sorting the address translation information included in the copy of the address translation table in an order determined by physical addresses included in the address translation information;
• reading from the disk array a physical stripe determined by the order of the physical addresses, in accordance with an address translation table in which the address translation information is sorted;
• managing a physical stripe which is to be read in said reading, as a first physical stripe of physically consecutive physical stripes ruled out from segment cleaning;
• and
• writing in the mass storage device a data block corresponding to a valid logical address included in the read physical stripe.