Patent ID: 7133985
Filing Date: 2006-11-07
Classification: G06F,Y10S

Abstract:
1. In a data storage environment having a first volume of data denominated as a source being stored on a data storage system, and a second volume of data denominated as a clone and which has data content that is a copy of a data content of the source being stored on the data storage system or on another data storage system, a method, operable on a computer system, for recovering the clone's data content in a situation wherein an operation to restore the source is interrupted during restoration of data from the second volume of data to the first volume of data, the method comprising the steps of: preserving the data content of the clone by not allowing it to be overwritten during restoration of the source, which restoration operation occurs when the data content of the source is replaced with the data content of the clone; creating a persistent map denominated as a persistent protected restore map to track extents of the source that are modified during the restoring and preserving steps; creating a persistent map denominated as a persistent clone delta map to track extents of the clone that be different between the clone and the source; and in response to an interruption of a restore operation of the source, using the persistent protected restore map and the persistent clone delta map to resume the restore operation that had been interrupted by determining whether corresponding bits in the delta map are set and corresponding bits in the persistent protected restore map are not set.