Patent ID: 6282619
Filing Date: 2001-08-28
Classification: G06F

Abstract:
In a RAID system for use with removable and identifiable storage devices that can be attached to said RAID system at a plurality of different attachment points, the method of migrating data in a logical media drive comprising the steps of:determining that the source RAID level is one;determining that the destination RAID level is five;determining that a number of destination devices to which data is to be migrated is greater than a number of source devices from which data is to be migrated, plus one;determining that the number of migrations required to migrate all of the data while preserving data integrity is two;determining that the direction of a first migration is from bottom up;determining that the direction of a second migration is from top down;defining a start logical block address of the first migration to be a stripe unit size times the number of destination devices minus two times the stripe unit size;defining the end logical block address of the first migration to be zero;defining a start logical block address of the second migration to be the stripe unit size times the number of destination devices minus the stripe unit size;defining the end logical block address of the second migration to be the lesser of a logical source end block address and a logical destination end block address;performing each migration by moving data from the source physical blocks to the destination physical blocks starting with the physical block corresponding to the start logical block address and continuing to the physical block corresponding to the end logical block address.