International Business Machines Corporation

Olga Yiparaki

Yan Xu

Christopher Michael Sansone

Lee Charles LaFrese

Dana Fairbairn Scott

Robert H Bell, Jr

Michael D Roll

Vernon Walter Miller

Joshua Douglas Martin

Justin Thomson Miller

Lee Charles La Frese

James Russell Thompson

Provided are a computer program product, system, and method for determining server write activity levels to use to adjust write cache size. Server write activity information on server write activity to the cache is gathered. The server write activity information is processed to determine a server write activity level comprising one of multiple write activity levels indicating a level of write activity. The determined server write activity level is transmitted to a storage server having a write cache, wherein the storage server uses the determined server write activity level to determine whether to adjust a size of the storage server write cache.

Determining server write activity levels to use to adjust write cache size

Provided are a computer program product, system, and method for determining server write activity levels to use to adjust write cache size. Information on server write activity to the cache is gathered. The gathered information on write activity is processed to determine a server write activity level comprising one of multiple write activity levels indicating a level of write activity. The determined server write activity level is transmitted to a storage server having a write cache, wherein the storage server uses the determined server write activity level to determine whether to adjust a size of the storage server write cache.

A mechanism for selectively disabling and enabling read caching based on past performance of the cache and current read/write requests. The system improves overall performance by using an autonomic algorithm to disable read caching for regions of backend disk storage (i.e., the backstore) that have had historically low cache hit ratios. The result is that more cache becomes available for workloads with larger hit ratios, and less time and machine cycles are spent searching the cache for data that is unlikely to be there.

Method for selectively enabling and disabling read caching in a storage subsystem

Host input/output (I/O) operations are performed via a file stored in a non-volatile storage coupled to a storage controller while data structures are being generated in the storage controller to copy data from source logical volumes to target logical volumes. The source logical volumes and the target logical volumes are logical representations of physical storage maintained in a plurality of direct access storage devices. The contents of the file are transferred from the non-volatile storage to one or more of the plurality of direct access storage devices, after the data structures have been generated, wherein the host I/O operations are performed via the file while the contents of the file are being transferred to the one or more of the plurality of direct access storage devices. The host I/O operations to the plurality of direct access storage devices are resumed, in response to transferring entire contents of the file to the one or more of the plurality of direct access storage devices.

Executing host data transfer operations during setup of copy services operations

An apparatus, system and method to optimize load distribution across logical and physical resources in a storage system. An apparatus in accordance with the invention may include an availability module and an allocation module. The availability module may dynamically assign values to resources in a hierarchical tree structure. Each value may correspond to an availability parameter such as allocated volumes, current resource utilization, and historic resource utilization. The allocation module may serially process the values and allocate a load to a least busy resource in the hierarchical tree structure based on the assigned values.

System and method for identifying least busy resources in a storage system using values assigned in a hierarchical tree structure

A method to store point-in-time data, comprising establishing a block size, providing source data storage comprising (S) blocks, and target data storage comprising (T) blocks. The method configures (B) source storage segments and (B) target storage segments, and receives updated point-in-time data for original point-in-time data written to an (i)th source storage segment. The method then determines if a (j)th target storage segment comprises available storage capacity to store the original point-in-time data. If a (j)th target storage segment comprises available storage capacity to store the original point-in-time data, the method writes the original point-in-time data to that (j)th target storage segment.

Apparatus and method to store original point-in-time data

Provided are techniques for introducing a delay in responding to host write requests. A percentage of fullness of a write cache is determined. Based on the determined percentage of fullness of the write cache (f), a low cache threshold (L), alpha (&#x3b1;), and k, an amount of delay to introduce into responding to a host write request is determined. Techniques wait the amount of the delay before responding to the host write request although the host write request processing has completed.

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Tucson, AZ, United States of America

Olga Yiparaki