Method and apparatus for migrating data having a format of a first type to a format of a second type

摘要

A method and apparatus that moves data stored in a first (e.g., 512) byte sector format to a second (e.g., 52x) byte sector size. The method and apparatus performs data migration without interruption of the host's ability to write and read data from the system. By migrating data to a number of new drives added to the system drive, the additional data which will be stored may be accommodated. The added drives allow the migration to take place without interruption of the hosts I/O path or allows the data to be migrated to an entirely new set of physical drives. The present invention also provides the ability to migrate data between sector sizes and still protect against component failures. The migration is performed in such a way that if a controller fails while performing the migration the survivor controller will be able to pick up where the failed controller left off. This is done through checkpoints in the migration process and saving information to a non-volatile memory which allows for resumption of the migration process.