Patent attributes
Embodiments for enabling granular migration of data with high efficiency. A defined metadata element, a tag, is assigned to each file, and then tag filtering is used to direct the data to the proper location. Files with different tags can be selected for transfer, and such a group of tags is referred to as a tag set. Embodiments can be used with a defined backup system file migration process, such as present in the Data Domain File System. By using snapshots, incoming new data (ingested file) is allowed to continue while the migration is in process and maintaining data consistency at the same time. This is achieved by performing operations on B+ Tree snapshots in conjunction with tag filtering on keys present in the leaf pages of these structures. This method is efficient became it makes a single pass walk of a B+ Tree in contrast with previous methods that look up files one-by-one via their pathname.