International Business Machines Corporation

Kevin Curtis Griffin

Glen Warren Nelson

David Glenn Carlson

Michael James McDermott

Scott Dennis Helt

William Anton Brown

Mark Philip Piazza

Richard James Eickemeyer

Gary Ross Ricard

Steven R Kunkel

Michael Joseph Corrigan

Thomas Paul Giordano

Mikko Herman Lipasti

Ross Evan Johnson

James Gregory Ranweiler

James L Denton

Sandra Kay Ryan

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

Techniques for recycling segment pages while preserving integrity of memory addressing. Upon a request to delete a system object, an initial segment identifier is de-assigned from a segment of the system object, and each segment page of the system object is remapped to a new virtual address range. The segment is stored as a reusable segment in a reusable segment store. Upon a request to access the system object, an exception is raised that the system object does not exist. Upon a request to create a new system object, the reusable segment store is searched to identify the reusable segment as a match. The reusable segment is assigned as a segment of the new system object.

Recycling segment pages while preserving integrity of memory addressing

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

An apparatus, clustered computer system, program product and method utilize a unique prepare operation in connection with a resource action to effectively 'lock out' missing or inactive cluster entities such as nodes and cluster objects from rejoining a clustered computer system subsequent to the resource action. The prepare operation includes the modification of one or more cluster configuration parameters associated with a plurality of entities in a clustered computer system, such that any such cluster entity that is active during the prepare operation accepts the modifications, while any such cluster entity that is inactive during the prepare operation does not accept the modifications. By modifying cluster configuration parameters for active cluster entities, attempts by previously-inactive cluster entities to activate or rejoin clustering subsequent to resource actions will generally fail due to an incorrect or stale cluster configuration parameters for such entities, and as a result, such entities will be effectively blocked from being accepted into the clustered computer system.

Cluster resource action in clustered computer system incorporation prepare operation

Logic for decreasing the number of cache lines dedicated to user data. When pools for allocation are selected using a dynamic storage allocation procedure, the size of a data block is compared to the size of the allocated pool. If the comparison results meet a predetermined criterion, the logic aligns the data to the beginning of a cache line and places the header in a separate cache line that may be deallocated. And if the data will fit within one-half of a cache slot in the allocated pool, then the line or lines having the header data can be re-used as the header is deallocated. Otherwise, user data blocks are placed in cache lines that are spatially local.

System and method for increasing cache efficiency through optimized data

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Rochester, MN, United States of America

Kevin Curtis Griffin