Methods and structure for improved import/export of RAID level 6 volumes

摘要

Methods and structure for improved import/export of RAID level 6 logical volumes in subsystems supporting RAID level 5 but not level 6. When a RAID level 6 logical volume is imported into a RAID level 5 storage subsystem, features and aspects hereof re-map the logical volume for use as a RAID level 5 logical volume. Disk blocks containing the level 6 additional redundancy information are not used by the RAID level 5 storage subsystem but are skipped in the re-mapping of the logical volume. All other blocks of the logical volume are mapped to corresponding blocks of the RAID level 6 mapping of the logical volume. The logical volume may then be flagged to indicate the additional redundancy information is invalid. A RAID level 6 storage subsystem may then rebuild the additional redundancy information when the flagged logical volume is re-imported to a RAID level 6 storage subsystem.