Fujitsu Corporation

Tadashi Hirano

Yukihiro Yoshiya

Kazuhiko Ikeuchi

Mikio Ito

Hidejirou Daikokuya

Hiroaki Sato

Hideo Takahashi

Norihide Kubota

Yoshihito Konta

Eisaku Takahashi

Yasutake Sato

Naoyoshi Toshine

Yuji Noda

Yusuke Inai

Masaru Shimmitsu

Nobuyuki Kikuchi

Kuniko Omido

Tsuyoshi Nakagami

Masami Ikeno

Yuuji Noda

A disk controller includes a determining unit for determining whether check codes added to data read from a disk drive are first type check codes or second type check codes, and a check code conversion unit. The check code conversion unit includes conversion unit for converting, if the check codes added to the read data are first type check codes, the first type check codes into second type check codes and a writing unit for writing the data provided with the second type check codes into the disk drive. The disk controller also includes a control unit for performing background processing, which is performed at a time different from processing performed when a data read request or a data write request is sent from a host device, by reading data provided with check codes from the disk drive and by starting check code conversion processing performed by the check code conversion unit.

Disk controller

In a storage system, a disk device performs recovery and transfers read data to a control device, and the control device judges the validity of the recovery to prevent a transfer of erroneous data. A control device read-accesses a disk device, and the disk device returns read data and a recovered read error response. A control device, at the time of an initial recovered read error, performs a retry of a similar command, and if an error does not occur for read commands including the retry read command, judges the data to be valid. Uncertain data (suspect data) upon occurrence of a recovered read error is restored through disk retry, and accurate read data can be transferred to the host.

Storage system, storage control device, and storage control method detecting read error response and performing retry read access to determine whether response includes an error or is valid

A RAID device changes the redundancy of the RAID configuration, while allows various RAID level conversions and capacity increase. Using new and old RAID configuration definition information which define at least a RAID level and a number of logical devices, the control unit performs RLU mapping based on the respective RAID configuration definition information, and performs staging and write back to change the RAID configuration. Therefore various RAID level conversions and capacity increase can be implemented.

RAID apparatus and logical device expansion method thereof

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Kahoku, Japan

Tadashi Hirano