1. A method for reorganizing an index file on a storage system using a computer, the index file having a tree structure with tree and leaf pages, the tree pages for indicating the logical order of tree pages and leaf pages, the method comprising the steps of: reading the tree pages to determine the logical order of the leaf pages; preparing a buffer correlating the leaf page physical position with its logical position for each leaf page; preparing a large buffer for receiving a copy of all the leaf pages in the index file; sequentially reading the leaf pages from the index file; for each sequentially read leaf page, determining the leaf page logical position by reference to said physical to logical buffer and placing the read leaf page in said large buffer at a location corresponding to the leaf page logical location; sequentially writing the contents of said large buffer to a new index file; and substituting said new index file for the index file being reorganized.