US 5,996,054 AGranted

Efficient virtualized mapping space for log device data storage system

AssigneeVeritas Software Corporation

InventorsJoel E. Ledain, John A. Colgrove, Dan Koren

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Abstract

A log device based data storage subsystem provides for the efficient storage and retrieval of data with respect to an operating system executing on a computer system coupled to the data storage system. The data storage system includes a storage device providing for the storage of predetermined file and system data, as provided by the computer system, within a main filesystem layout established in the storage device. The data storage system also includes a log device coupled in the logical data transfer path between storage device and the computer system. The log device provides for the storage of the predetermined file and system data within a log structured filesystem layout established in the log device. A control program, included as part of the data storage system, is executed in connection with the log device and provides log structured filesystem management over the log device to store the predetermined file and system data in one of a plurality of data segments, delimited by a first free data segment and an oldest filled data segment, to selectively clean the oldest filled data segment to the first free data segment, and to selectively transfer the predetermined file and system data from the log device to the storage device. The control program utilizes location data provided in the predetermined file and system data to identify a destination storage location for the predetermined file and system data within the main filesystem layout.

A log device system coupleable to a computer system that executes an operating system that includes a filesystem, said computer system further including (i) a primary storage device, including a first rotating media controller, having a first data storage space provided on a first non-volatile rotating media, said filesystem directing the storage of filesystem data blocks within said first data storage space, and (ii) a primary device driver, executable by said computer system in connection with the execution of said operating system, that manages the transfer of filesystem data blocks with respect to said primary data storage device within a first real addressable storage space, said log device system comprising:

a) a log storage device including a second rotating media controller, having a second data storage space provided on a second non-volatile rotating media, said second data storage space providing for the storage of data segments within a second real addressable storage space;
and
b) a log device driver, executable by said computer system in connection with the execution of said operating system, that manages the transfer of data with respect to said log storage device, said log device driver implementing a virtual address storage space that corresponds to said first real addressable storage space and utilizing a translation map relating a predetermined set of addresses within said first real addressable storage space with a predetermined address within said second real addressable storage space, said log device driver providing for predetermined filesystem data blocks to be stored with data defining a corresponding portion of said virtual address storage space and for said predetermined filesystem data blocks to be stored within a predetermined data segment, said log device driver being coupleable to said filesystem and to said primary device driver to transfer filesystem data blocks thereinbetween upon reference to said first real addressable storage space by said filesystem.

Abstract

Claims10