Abstract: Methods, apparatus and computer program products implement embodiments of the present invention that enable digital information devices having respective storage devices and memories to distributedly store, for a logical volume, data and first and second parity values across corresponding regions of the storage devices. Freezers having a one-to-one correspondence with the storage devices are distributedly stored in the memories. Upon detecting, in a cache, updated data for one or more first regions on the storage devices, existing data from the one or more first regions, and additional data for parity calculations are retrieved from one or more corresponding second regions on the storage devices, and first and the second parity values are calculated using the updated data, the existing data and the additional data, and the updated data and the calculated first and second parity values are stored to the freezers.

Abstract: Methods, apparatus and computer program products for a distributed system include dividing logical volume data into data subsets, and defining at least one distributedly storage configuration for the logical volume. Metadata for the logical volume is written to a first set of first metadata tables, and the first set of first metadata tables is divided into metadata subsets having a one-to-one correspondence with the data subsets. The metadata subsets are distributed among the multiple digital information devices, and the metadata is copied from the first set of first metadata tables to a second set of corresponding second metadata tables in a one-to-one correspondence with the first metadata tables, and the second metadata tables are distributed among the multiple digital information devices.

Abstract: Methods, apparatus and computer program products for a distributed system include dividing logical volume data into data subsets, and defining at least one distributedly storage configuration for the logical volume. Metadata for the logical volume is written to a first set of first metadata tables, and the first set of first metadata tables is divided into metadata subsets having a one-to-one correspondence with the data subsets. The metadata subsets are distributed among the multiple digital information devices, and the metadata is copied from the first set of first metadata tables to a second set of corresponding second metadata tables in a one-to-one correspondence with the first metadata tables.

Abstract: A computing device receives a plurality of writes; each write is comprised of chunks of data. The computing device records metrics associated with the deduplication of the chunks of data from the plurality of writes. The computing device generates groups based on associating each group with a portion of a range of the metrics, such that each of the chunks of data are associated with one of the groups, and a similar number of chunks of data are associated with each group. The computing device determines a deduplication affinity for each of the groups based on the chunks of data that are duplicates and at least one metric. The computing device sets a threshold for the deduplication affinity and in response to any of the groups exceeding the threshold, the computing device excluding the chunks of data associated with a group exceeding the threshold, from deduplication.

Abstract: Methods, apparatus and computer program products implement embodiments of the present invention that enable digital information devices having respective storage devices and memories to distributedly store, for a logical volume, data and first and second parity values across corresponding regions of the storage devices. Freezers having a one-to-one correspondence with the storage devices are distributedly stored in the memories. Upon detecting, in a cache, updated data for one or more first regions on the storage devices, existing data from the one or more first regions, and additional data for parity calculations are retrieved from one or more corresponding second regions on the storage devices, and first and the second parity values are calculated using the updated data, the existing data and the additional data. The updated data and the calculated first and second parity values are stored to the freezers, and then destaged from the freezers to the storage devices.

Abstract: Methods, apparatus and computer program products for a distributed system include dividing logical volume data into data subsets, and defining at least one distributedly storage configuration for the logical volume. Metadata for the logical volume is written to a first set of first metadata tables, and the first set of first metadata tables is divided into metadata subsets having a one-to-one correspondence with the data subsets. The metadata subsets are distributed among the multiple digital information devices, and the metadata is copied from the first set of first metadata tables to a second set of corresponding second metadata tables in a one-to-one correspondence with the first metadata tables. The second metadata tables are distributed among the multiple digital information devices, and upon modifying the metadata in a one of the first metadata tables while processing a storage request, the corresponding second metadata table is revised with the updated metadata.

Abstract: A method for improving I/O performance using queuing latency feedback initially generates, at a host system, I/O for processing on a storage system. The I/O is received at the storage system and queuing latency experienced by the I/O is measured as the I/O is processed by the storage system. The queuing latency is returned to the host system. The host system may use the queuing latency to understand delays and resource contention within the storage system and enable the host system to more effectively take actions that improve I/O performance and compliance with SLAs. A corresponding system and computer program product are also disclosed.

Abstract: Aspects of the invention are provided for decoding a selected span of data within a compressed code stream. A selection of data within the compressed code stream from an arbitrary position is presented for decompression. The arbitrary position is the starting point in the compressed code stream for decompression, and a phrase within the compressed code stream containing the starting point is identified. From the arbitrary starting point, a back pointer may provide direction to the literal. The literal is extracted as a decoding of the compressed data associated with the starting point.

Abstract: Embodiments of the invention relate to data placement for loss protection in a storage system. One embodiment includes constructing multiple logical compartments. Each logical compartment includes a placement policy including a set of storage placement rules for determining permitted placement of storage symbols on specific physical storage containers, and a balancing policy for determining a particular placement of the storage symbols among permitted placements for balancing the storage symbols for each volume among the physical storage containers that is useable within the placement policy.

Abstract: A multi-mainframe operating system serialization method can include receiving, in a first computing system, a request to access a data set on behalf of a first peer application, sending, in the first computing system, a notification to a second peer application to obtain a normal enqueue, in response to the second peer application obtaining the normal enqueue, obtaining, in the first computing system, a first rider enqueue for the data set and sending, in the first computing system, a communication to peer instances to obtain additional rider enqueues for the data set, the additional rider enqueues corresponding to the first rider enqueue.

Abstract: A heterogeneous computing system includes a first server module having a first operating system, a second server module communicatively coupled to the first server module, the second server module having a second operating system dissimilar to the first operating system, a data set accessible by the first server module and the second server module; and a process residing on the first server module, the process configured to grant access to the second server module, from the first server module, to the data set.

Abstract: Embodiments relate to a method for data management. An aspect includes a method for assigning storage types to data based on access frequency. Past or historical data associated with current data usage is also considered prior to assignment. Once data frequency access is determined, the current data is assigned to a first tier of a plurality of hierarchical ordered tiers, each tier corresponding to at least one class of storage. In one embodiment, there may be a condition that overrides the assignment with option to override it. The tier assignment may also be preserved the tier so that the current data can be appropriately assigned in the future.

Abstract: A multi-mainframe system problem determination method includes receiving, in a first computing system, a data collection trigger, coordinating, in the first computing system, synchronized diagnostic data collection with a second computing system, and delivering the diagnostic data to a storage medium.

Abstract: A multi-mainframe system problem determination method includes recording, in a first computing system, diagnostic data, receiving, in the first computing system, a data collection trigger, responsive to the data collection trigger, coordinating, in the first computing system, synchronized collection of recorded diagnostic data with a second computing system and delivering collected diagnostic data to a storage medium.

Abstract: Embodiments relate to a system and computer program product for data management. An aspect includes a method for assigning storage types to data based on access frequency. Past or historical data associated with current data usage is also considered prior to assignment. Once data frequency access is determined, the current data is assigned to a first tier of a plurality of hierarchical ordered tiers, each tier corresponding to at least one class of storage. In one embodiment, there may be a condition that overrides the assignment with option to override it. The tier assignment may also be preserved so that the current data can be appropriately assigned in the future.

Abstract: Embodiments of the invention relate to data placement for loss protection in a storage system. One embodiment includes constructing multiple logical compartments. Each logical compartment includes a placement policy including a set of storage placement rules for placement of storage symbols into a set of physical storage containers. A first logical compartment of said plurality of logical compartments is container-overlapped with respect to a second logical compartment of said plurality of logical compartments. The first logical compartment is data loss independent with respect to the second logical compartment. Each of multiple storage volumes is associated with a logical compartment. The storage symbols that represent a data stripe are placed onto physical storage containers in conformity with the placement policy associated with the logical compartment containing the data stripe.

Abstract: Embodiments of the invention are provided to enable fair and balanced allocation of control blocks to support processing of requests received from a client machine. The server is configured with tools to manage an account balance of control block availability for each service class. The account balance is periodically adjusted based upon usage, tenancy, deficits, and passage of time. Processing of one or more tasks in a service class is support when the credit value in the service class account is equal to or greater than the entry cost estimated for the request.

Abstract: A computing device receives a plurality of writes; each write is comprised of chunks of data. The computing device records metrics associated with the deduplication of the chunks of data from the plurality of writes. The computing device generates groups based on associating each group with a portion of a range of the metrics, such that each of the chunks of data are associated with one of the groups, and a similar number of chunks of data are associated with each group. The computing device determines a deduplication affinity for each of the groups based on the chunks of data that are duplicates and at least one metric. The computing device sets a threshold for the deduplication affinity and in response to any of the groups exceeding the threshold, the computing device excluding the chunks of data associated with a group exceeding the threshold, from deduplication.

Abstract: Migrating a sub-volume in data storage with at least two de-duplication domains, each of the domains having at least one sub-volume. A first sub-volume is assigned to a de-duplication domain and a first content summary is computed for the first sub-volume. Similarly, a second sub-volume is assigned to a second de-duplication domains and a second content summary is computed for the second sub-volume. A first content affinity is calculated between the first sub-volume and a third sub-volume, and a second content affinity is calculated between the second sub-volume and the third sub-volume. A domain placement is selected for the third sub-volume based on comparison of the first content affinity and the second content affinity.

Abstract: Assignment of files to a de-duplication domain. Address space of data files is divided into multiple containers. For each of the containers, a file metadata scan is performed to obtain file system metadata, which is aggregated and summarized in a content feature summary. A content feature summary prediction measurement is measured between containers from the generated content feature summary, and files from each container are assigned to a de-duplication domain based upon the content similarity predication measurement.