International Business Machines Corporation

Tim Stephen Vande Zande

Michael T Benhase

David Frank Mannenbach

Said Abdullah Ahmad

Kevin J Ash

Joseph Dean Ohrazda

Richard H Grossman

Pablo A Rodriguez

Provided are a method, system, and article of manufacture for validating stored copies of data images to load into memory. An image of data is maintained in a memory, wherein the image in the memory includes a generation number. The image in the memory is written to at least two copies of the image to storage locations in response to a first event, wherein the generation number for the image in the memory is stored in the storage locations having the copies of the image. A check generation number is stored in a storage location. The image is loaded from at least one of the copies of the image in one of the storage locations to the memory in response to a second event The generation number for the image loaded into the memory. The check generation number is incremented in response to the second event. The generation numbers for the copies of the image in the storage locations and the check generation number are used to validate the copies of the image.

Validating stored copies of data images to load into memory

Provided are a method, system, and article of manufacture for validating stored copies of data images to load into memory. An image of data is maintained in a memory, wherein the image in the memory includes a generation number. The image in the memory is written to at least two copies of the image to storage locations in response to a first event, wherein the generation number for the image in the memory is stored in the storage locations having the copies of the image. A check generation number is stored in a storage location. The image is loaded from at least one of the copies of the image in one of the storage locations to the memory in response to a second event. The generation number for the image loaded into the memory. The check generation number is incremented in response to the second event. The generation numbers for the copies of the image in the storage locations and the check generation number are used to validate the copies of the image.

A data storage control unit is coupled to one or more host devices and to one or more physical storage units, the storage control unit configured as a plurality of clusters. Each cluster includes cache memory and often non-volatile storage (NVS). The storage control unit receives and processes write requests from the host devices and directs that data updates be temporarily stored in the cache in one cluster and copied to the NVS of the other cluster. The data updates are subsequently destaged to the logical ranks associated with each cluster. During an initial microcode load (IML) of the storage controller, space in the cache and NVS of each cluster is allocated to buffers with the remaining cache and NVS space being allocated to customer data. After an IML has been completed, the size of the buffers become fixed and no further buffer allocation may occur. Method, apparatus and program product are provided by which a data storage controller dynamically reconfigures NVS and cache memory in multiple clusters, particularly when it is desired to change the size of the NVS and cache of either or both clusters.

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Tucson, AZ, United States of America

Tim Stephen Vande Zande