Patent ID: 8032703

Claim:
A storage apparatus which distributively writes user data provided from a host apparatus, together with redundant data created based on the user data, into a plurality of storage mediums, comprising: a management unit for managing whether the user data is written in each stripe, which is a unit area for reading and writing the user data, in a storage area provided by the plurality of storage mediums; and a correction copy processing execution unit for executing to each of the stripes correction copy processing of recovering, when any one of the storage mediums is blocked due to a failure, data stored in that storage medium and copying the data to a spare storage medium; and wherein the correction copy execution unit executes the correction copy processing to the stripe written with the user data in preference to the stripe not written with the user data in a storage area provided by the plurality of storage mediums, and executes the correction copy processing to the stripe not written with the user data in a storage area provided by the plurality of storage mediums during its spare time, wherein a corresponding flag is provided to each of the stripes; wherein, when user data from the host apparatus is written into a storage area provided by the plurality of storage mediums, the management unit changes the status of the flag associated with the stripe written with the user data to a prescribed status; and wherein the failure recovery unit determines whether the user data is written into a target stripe based on the status of the flag upon executing the correction copy processing to the stripe written with the user data.