Patent ID: 6636879
Filing Date: 2003-10-21
Classification: G06F,Y10S

Abstract:
A method for improved space allocation in a write anywhere file system, including a file system having a set of storage blocks in a mass storage system, includingmaintaining an active map of said storage blocks not available for writing data; recording a consistency point in said file system including a consistent version of said file system at a previous time, said consistency point including a copy of said active map at said previous time; determining, for each one of a plurality of regions of said storage blocks in said mass storage system, a spacemap including an array of binary numbers, each said binary number being count related to a number of blocks available or not available for writing data in one of said regions, wherein said spacemap is responsive to said active map and a summary map; and selecting at least one of said plurality of regions in response to said spacemap.