Log device layered transparently within a filesystem paradigm

A data storage subsystem for use cooperatively with a computer system including a filesystem and a main device driver coupling said filesystem to a main mass storage disk drive for the storage and retrieval of data identifiable by disk identification and main storage address, said data storage subsystem comprising:

• a) a log mass storage disk drive providing for the storage of data in a plurality of segments;
• and
• b) a log device driver selectively coupleable between said filesystem and said main device driver, said log device driver providing for the selective construction and storage of a predetermined data block within a predetermined one of said segments from data directed by said filesystem to be stored at a predetermined main storage address, said log device driver providing for the establishment of a translation map relating said predetermined main storage address with said predetermined one of said segments.

A data storage subsystem transparently and selectively providing an optimized write data path for logical data blocks provided by a filesystem of an operating system executable by a computer system that nominally provides for the storage of logical data blocks on a main filesystem disk drive at locations defined by logical data block numbers, said data storage subsystem comprising:

• a) log device disk drive providing for the storage of a plurality of data segments, each including a respective plurality of logical data blocks, and wherein said plurality of data segments are stored by said log device disk drive at locations defined by segment numbers;
• and
• b) a device driver executable in support of said filesystem to organize a plurality of predetermined logical data blocks into a first predetermined data segment and directing the storage of said predetermined data segment to said log device disk drive, said device driver providing for the construction of a location translation map system relating the logical data block numbers of said predetermined logical data blocks to a first predetermined segment number identifying said first predetermined data segment, said device driver supporting the partitioning of said translation map system into map blocks substitutable as logical data blocks within a second predetermined data segment storable by said log device disk drive.

A data storage subsystem providing a write optimized data storage path in a computer system having a main storage device provided to store data blocks at respective main store addresses, said data storage system comprising:

• a) a log device providing a log structured storage space for a data segment, said log device being coupleable to the computer system to establish a data transfer path between the computer system and said log device;
• and
• b) a control program, executable by said computer system, providing for the processing of a predetermined data block and a corresponding predetermined main store address into a user data block and transfer of said user data block to said log device for storage in said data segment, and further providing for the transfer of said user data block to said computer system to allow storage of said predetermined data block in said main storage device at said corresponding main store address.