US Patent 10970251 Managing storage system metadata during data migration

Data is migrated from a source storage device to a destination storage device using tape media. Both the source storage device and the destination storage device utilize disk drives to store data. A portion of data is detected migrating to the tape media. Metadata of the portion of data is changed to identify the portion of data as residing on the tape media. A prefetch command for the portion of data is detected. It is determined that the portion of data is stored on the tape media. In response to determining that the portion of data is stored on the tape media, the prefetch command is executing without recalling the portion of data to the disk drives. Instead, the portion of data is read directly from the tape media.