Patent ID: 7249277

Claim:
A storage apparatus, comprising: a plurality of drive cases in each of which a plurality of units are detachably mounted, each of the units including a plurality of drives that are detachably mounted; and a controller case in which a disk control section is provided, in which RAID groups each are composed of disks included in the plurality of units, the disk control section comprising: a drive state management table recording a state of each of the drives, a RAID group state management table recording a state of each of the RAID groups, a number of background processings indicating under execution data rebuilding processing to a RAID group and data copy processing between drives, a fault detection section for changing a state of the fault drive in the drive state management table to “fault” when a fault drive is detected, and a state of a RAID group to which the fault drive is assigned in the RAID group state management table to “fault”; a judging section for judging whether a redundancy of the RAID group to which the fault drive is assigned is smaller than a guaranteed redundancy and equal to or larger than zero, and for judging whether a redundancy of a RAID group to which another drive included in a unit including the fault drive is assigned is smaller than the guaranteed redundancy and equal to or larger than zero; a data rebuilding section for changing a state of a spare drive searched from a unit other than the unit including the fault drive to “rebuilding” and rebuilding data in the fault drive to the spare drive when the redundancy of the RAID group to which the fault drive is assigned is smaller than the guaranteed redundancy and equal to or larger than zero, and incrementing the number of background processings by one during rebuilding processing; a data copying section for changing a state of a spare drive searched from a unit other than the unit including the other drive to “refuging” and copying data from the said other drive to the spare drive when the redundancy of the RAID group to which the said other drive is assigned is smaller than the guaranteed redundancy and equal to or larger than zero and incrementing the number of background processings by one during data copying processing; and an exchange indicating section for judging whether processings of the data rebuilding section and the data copying section are complete based on the number of background processings and giving a notice that the fault drive and the unit including the fault drive are ready to exchange when these processings are complete.