Abstract: A policy-based data management system, method, and apparatus are disclosed. The system, method, and apparatus are configured to operate over a distributed storage system such as a storage area network (SAN). Files to be stored on the network are each assigned a service class and a storage pool based on the application of policies to file attributes such as file name, type, user, etc. The service class and storage pool designations are stored as metadata. Files may be retrieved using the metadata to identify the storage pool where the file is stored, and the service class listed within the metadata may be used to control the manner in which the file is handled. A metadata server may be utilized to provide the appropriate service class of files in response to requests from remote clients that may be of different computing platforms.

Abstract: A policy-based data management system, method, and apparatus are disclosed. The system, method, and apparatus are configured to operate over a distributed storage system such as a storage area network (SAN). Files to be stored on the network are each assigned a service class and a storage pool based on the application of policies to file attributes such as file name, type, user, etc. The service class and storage pool designations are stored as metadata. Files may be retrieved using the metadata to identify the storage pool where the file is stored, and the service class listed within the metadata may be used to control the manner in which the file is handled. A metadata server may be utilized to provide the appropriate service class of files in response to requests from remote clients that may be of different computing platforms.

Abstract: Non-disruptive data migration moves are performed form a source DASD to target DASD in a data subsystem. Both source and target DASDs comprise a cache and a nonvolatile store (NVS). Relative to the host, the target DASD generally operates as a source, managing requests for access to source DASD data by issuing I/O requests to the source DASD. First, the target DASD initiates a background data transfer, where data is copied from the source DASD to the target DASD preparing the target DASD to replace the source DASD. The data transfer includes copying data items directly from the source DASD's cache to that of the target DASD's cache, as well as copying data items from the source DASD's NVS to the target DASD's NVS. During background data transfer, the host can still perform data access operations, such as reads and writes, using the target DASD. Namely, for data already copied from the source DASD to the target DASD, the host reads this data from the target DASD.

Abstract: A multi-node video server system in accordance with the invention comprises disk storage associated with a first node which stores at least a portion of a video presentation in the form of plural data blocks, each data block comprising a viewing time segment of the presentation. RAM buffer in a second node receives and stores data blocks of the video presentation from the disk storage in the first node, upon an initial request by a first viewing terminal to view a portion of the video presentation. A communication module in the second node outputs the data blocks, as an isochronous data stream, to requesting terminals. A host controller is coupled to the video server nodes and receives requests from viewing terminals for the video presentation. The host controller causes the communication module in the second node to connect to a viewing terminal which renders the initial request.

Abstract: Primary and secondary data processing systems are coupled via a communication system. Data storage in both systems is provided by a log structured array (LSA) system that stores data in compressed form. Each time data are updated within LSA, the updated data are stored in a data storage location different from the original data. Selected data recorded in a primary data storage of the primary system is remote dual copied to the secondary system for congruent storage in a secondary data storage, such as for disaster recovery purposes. The primary systems creates a remote copying session. Within such remote copying session, a series of "pending write update" sessions are ESTABLISHED. All data updated within each pending write update session is a consistency group of data. Within each pending write update session update data are retentively stored in both the primary and secondary systems (such as in a non-volatile cache).