International Business Machines Corporation

Michael Robert Groseclose, Jr

Jason Lee Peipelman

Larry Juarez

David Montgomery

Joshua M Rhoades

Todd Charles Sorenson

Paul Anthony Jennas, Ii

Philip Matthew Doatmas

Brian Sean McCain

Dale Howard Anderson

Yang Liu

Michael Paul Groover

Franck Excoffier

Xu Han

Mario Kiessling

David Montogmery

A data storage subsystem having a plurality of data compression engines configured to compress data, each having a different compression algorithm. A data handling system is configured to determine a present rate of access to data; select at least one sample of data; determine the greatest degree of compression of said data compression engines; determine the compression ratios of the operated data compression engines with respect to the selected sample(s); compressing said selected at least one sample with a plurality of said data compression engines at said selected tier; operate a selected data compression engines with respect to the selected sample and determine the greatest degree of compression of the data compression engines; compress the data from which the sample was selected with one of the operated data compression engines determined to have the greatest degree of compression; and store the compressed data in data storage repositories.

Data compression algorithm selection and tiering

A method for managing persistent data in a multi-image code load system is disclosed. In one embodiment, such a method includes providing first and second code images for loading onto a computing system. The method stores, in a common repository, persistent data that is shared by each of the first and second code images. When changes are made to the shared persistent data associated with the first and second code images, the changes are recorded in the form of content deltas. When generating such content deltas, the method determines which of the first and second code images the content deltas apply to and marks the content deltas accordingly. A corresponding apparatus and computer program product are also disclosed and claimed herein.

Persistent data management in multi-image code load systems

A data storage subsystem having a plurality of data compression engines configured to compress data, each having a different compression algorithm. A data handling system is configured to select at least one sample of data; operate a plurality of the data compression engines to compress the selected sample(s); determine the compression ratios of the operated data compression engines with respect to the selected sample(s); and select the data compression engine having the greatest compression ratio with respect to the selected sample(s), to compress the data. Further, the data compression engines may be in tiers from low to high in accordance with expected latency to compress data and to uncompress compressed data; and a data compression engine is selected from a tier that is inverse to the present rate of access.

A method for more effectively distributing the I/O workload in a data replication system is disclosed herein. In selected embodiments, such a method may include generating an I/O request and identifying a storage resource group associated with the I/O request. In the event the I/O request is associated with a first storage resource group, the I/O request may be directed to a first storage device and a copy of the I/O request may be mirrored from the first storage device to a second storage device. Alternatively, in the event the I/O request is associated with a second storage resource group, the I/O request may be directed to a second storage device and a copy of the I/O request may be mirrored from the second storage device to the first storage device.

Evenly distributing workload and providing a predictable failover scenario in a data replication system

A method for managing extents in a data storage system includes monitoring usage statistics for an extent residing on one or more powered-up storage devices. In the event the extent has not been accessed for specified period of time (as determined from the usage statistics), the method automatically compresses the extent and migrates the extent to an intermediate repository. Once the amount of data in the intermediate repository reaches a specified level, the method migrates the extent from the intermediate repository to one or more normally powered-down storage devices. If I/O is received for the extent while it resides in the normally powered-down storage devices or the intermediate repository, the method automatically migrates the extent from the normally powered-down storage devices or the intermediate repository to the normally powered-up storage devices. A corresponding apparatus and computer program product are also disclosed.

Data migration methodology for use with arrays of powered-down storage devices

A method for more effectively distributing the I/O workload in a data replication system is disclosed herein. In selected embodiments, such a method may include generating an I/O request and identifying a storage resource group associated with the I/O request. In the event the I/O request is associated with a first storage resource group, the I/O request may be directed to a first storage device and a copy of the I/O request may be mirrored from the first storage device to a second storage device. Alternatively, in the event the I/O request is associated with a second storage resource group, the I/O request may be directed to a second storage device and a copy of the I/O request may be mirrored from the second storage device to the first storage device. A corresponding system, apparatus, and computer program product are also disclosed and claimed herein.

A method, system, and computer program product for determining severity of communication deficiencies and isolating faults in a power network of a data processing environment is provided. Pursuant to a continuous graph theory analysis, each of a plurality of nodes of the power network is initialized with the same arbitrary value. Each of a plurality of network paths connecting each of the plurality of nodes is analyzed. Upon a successful communication or communication deficiency over one of the plurality of network paths, one arbitrary value of one of the plurality of nodes connected to the one of the plurality of network paths is incremented or decremented, respectively by a weighting value. The incrementing and decrementing is repeated until a threshold is reached and a recovery is performed on which of the plurality of nodes has a lower adjusted value.

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Tucson, AZ, United States of America

Michael Robert Groseclose, Jr