Patent ID: 6823436
Filing Date: 2004-11-23
Classification: G06F

Abstract:
A computer implemented method of maintaining usage metadata nodes about data snapshots of data present in data storage in a data processing system, comprising the steps of:forming a snapshot of data present in units of memory segments of the data processing system within a metadata tree log having a plurality of usage metadata nodes; scanning the usage metadata nodes within the metadata tree log for units of memory segments overlapping with the units of memory segments of the data in the snapshot resulting from the step of forming a snapshot; and if overlapping units of memory segments are found during the step of scanning, forming an entry in an associated bitmap, said entry corresponding to the usage metadata at locations indicating the memory segments found to overlap during the step of scanning; and modifying the metadata node to indicate that the usage metadata therein contains at least one entry at a location corresponding to an entry in said bitmap which identifies the memory segment to overlap.