| 摘要 |
An apparatus, system, and method are disclosed for online RAID set expansion from an amount of disks i to an amount of disks j, where j disks includes one or more new disks, with data integrity assurance during the expansion process. In accordance with the invention, data migration to the destination RAID set comprises segments with a variable length, such that a sub-stripe group of a certain size is included in each segment migrating within an identified destructive zone ("DZ") thereof, avoiding overwriting of any corresponding source data. Thus, the invention eliminates a requirement for data backup before migration to the DZ to protect against data loss due to a possible power failure. Beyond the DZ, data migration is allowed to proceed in segments with a different length, such as allowing a whole stripe group to migrate safely, so as to achieve a normally possible maximum efficiency.
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