Hitachi, Ltd.

Masaki Aizawa

Fumio Yamaguchi

Mikio Fukuoka

Eiju Katsuragi

Takeki Okamoto

Takashi Uchiyama

Hidehiko Kimura

Proposed are a copy system and a copy method capable of performing initial copy in a short amount of time and with high reliability. On a primary side, the area in the first volume to which data was written from the host is managed, a second bitmap is created reflecting the contents of the first bitmap, and the second bitmap is sent to the secondary side on the primary side. On a secondary side, a third bitmap to which the second bitmap sent from the primary-side is merged is created, on the primary side, only the valid data containing data written by the host in the first volume is copies to the second volume based on the second bitmap, and, on the secondary-side, the differential between the first and second volumes during the initial copy is managed based on the third bitmap.

Copy system and method using differential bitmap

A storage system and a backup method achieving enhanced reliability without degradation in the performance of the entire system. A first storage apparatus stores data transmitted from a host system and transmits it to a second storage apparatus and a third storage apparatus. The second storage apparatus and the third storage apparatus store the data transmitted from the first storage apparatus and verify the consistency in the data between themselves.

Storage system and backup method

The invention is intended to reduce disk access during data transfer from a disk in which occurrence of failure is anticipated to a spare disk as much as possible so that occurrence of double-failure is prevented in advance. When occurrence of failure in a disk which configures a RAID group, contents stored in the disk is copied to the spared disk. Simultaneously, another RAID group is paired with the above described RAID group and a secondary volume is provided therein. A write request is directed to the secondary volume. A differential bitmap controls a update data. Data which is not updated is read out from the primary volume, and data which is already updated is read from the secondary volume. When data transfer is completed, contents stored in the secondary volume are copied to the primary volume.

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Odawara, Japan

Masaki Aizawa