International Business Machines Corporation

Glen Warren Nelson

Kevin Curtis Griffin

Jay Paul Kurtz

Kenneth Charles Vossen

Michael Joseph Corrigan

Michael James McDermott

Scott Dennis Helt

Kenneth Gerald Linn

Larry J Cravens

Mark Philip Piazza

Donald L Ward

Bruce Marshall Walk

Gary Ross Ricard

David Glenn Carlson

Michael Steven Faunce

Timothy John Mullins

William Anton Brown

Patrick James Christenson

Thomas Richard Crowley

Russell Paul VanDuine

Embodiments are provided for deferring allocation of storage for segments. The method includes receiving, at a first moment in time, a request to allocate a first segment within a memory. Information corresponding to the first segment is stored in a first entry in a hash table, and memory is allocated for the first segment. Information about the first segment is returned to an entity that requested the allocation of the first segment, where the first segment is not allocated auxiliary storage until predefined criteria are satisfied. At a second moment in time, upon receiving an indication to deallocate the first segment, memory corresponding to the first segment is deallocated, where the first segment is never allocated auxiliary storage and the first entry in the hash table is deleted.

Deferred method of allocating disk space for lightning segments

An apparatus, method, and program product for optimizing a multiprocessor computing system by sampling memory reference latencies and adjusting components of the system in response thereto. During execution of processes the computing system, memory reference sampling of memory locations from shared memory of the computing system referenced in the executing processes is performed. Each sampled memory reference collected from sampling is associated with a latency and a physical memory location in the shared memory. Each sampled memory reference is analyzed to identify segments of memory locations in the shared memory corresponding to a sub-optimal latency, and based on the analyzed sampled memory references, the physical location of the one or more identified segments, the processor on which one or more processes referencing the identified segments, and/or a status associated with the one or more identified segments is dynamically adjusted to thereby optimize memory access for the multiprocessor computing system.

Dynamic process/object scoped memory affinity adjuster

A method, apparatus and computer program product are provided for implementing feedback directed deferral on nonessential direct access storage device (DASD) operations. A kernel DASD I/O manager maintains a queue depth count value for a DASD unit and maintains a busy flag that indicates when the queue depth count value is greater than a predefined threshold. The kernel DASD I/O manager defers optional operations responsive to the busy flag being set for the DASD unit.

Implementing feedback directed deferral of nonessential DASD operations

A method backs up computer data by organizing update requests into groups. All update requests in one group complete concurrently before requests of a subsequent group complete.

Asynchronous hybrid mirroring system

An apparatus and method provides the capability of mirroring storage from a primary system to a mirrored system in a way that uses parallelism in the mirrored system to maximize the efficiency of writing data to the mirrored storage for operations that do not conflict while serializing operations that do conflict. The mirroring of the present invention is 'logical mirroring', which does not require identical disk drives, and which supports mirroring between geographically remote locations to protect against catastrophic site failure. Parallelism is achieved in the mirrored system by dividing the virtual address space into multiple ranges, and by assigning a group of tasks to each range. When an operation is received on the mirrored system, the virtual address range that the operation affects is determined, and the operation is then delegated to the task group that corresponds to the affected virtual address range. By dividing the virtual address space into ranges, tasks in different ranges (i.e., in different task groups) may execute in parallel without any threat of conflict, and even tasks within the same range may execute in parallel if they operate in different portions of the range.

Apparatus and method for writing data to mirrored storage using multiple tasks working in parallel

Method and apparatus for managing data on DASD units to improve system performance comprises monitoring portions of data on a plurality of DASD units to determine the times the data is accessed within a given time period, and characterizing accessed data portions of a DASD unit as HOT and COLD data. The DASD units are monitored to determine the number of times each unit is accessed within a time period to develop utilization factors reflective of the number of times the DASD unit is accessed during the time period. HOT and COLD data is moved between DASD units based on the utilization factors of the DASD units.

Dynamic DASD data management and partitioning based on access frequency utilization and capacity

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Rochester, MN, United States of America

Glen Warren Nelson