Abstract: Computer program products, as well as corresponding systems and methods are configured for performing deduplication in conjunction with random read and write operations, and include: receiving a write request comprising data; computing a fingerprint of the data; determining whether a short term dictionary comprises an entry corresponding to the fingerprint; in response to determining the short term dictionary comprises the entry corresponding to the fingerprint, writing the data to a data store in a deduplicating manner; in response to determining the short term dictionary does not comprise the entry, determining whether a long term dictionary corresponding to the namespace comprises the entry; in response to determining the long term dictionary comprises the entry, writing the data to the data store in the deduplicating manner; and in response to determining the long term dictionary does not comprise the entry, writing the data to the data store in a non-deduplicating manner.

Abstract: In one embodiment, a computer program product is configured for performing deduplication in conjunction with random read and write operations across a namespace divided into a plurality of disjoint regions. The computer program product includes a computer readable storage medium having program instructions embodied therewith, where the computer readable storage medium is not a transitory signal per se. The program instructions are executable by a computer to cause the computer to perform a method including: maintaining a metadata structure for each of the plurality of disjoint regions via the respective region manager(s) of the plurality of disjoint regions, each metadata structure comprising metadata indicating a physical storage location of one or more data chunks associated with the respective region; and performing, by the computer, a deduplicated write operation of a first data chunk in a first region of the plurality of disjoint regions.

Abstract: Detecting data duplication includes maintaining a fingerprint directory including one or more entries. Each entry includes a data fingerprint and a data location for a data chunk. A shadow list including a record of fingerprint values not contained in the fingerprint directory is maintained. Each entry is associated with a seen-count attribute, which is an indication of how often a data fingerprint has been seen in arriving data chunks to be written in a storage system, and distinguishes multiply-seen entries for data fingerprints present in at least two data chunks from once-seen entries for data fingerprints present in no more than a single data chunk. Each entry retrieved from the shadow list relates to twice-seen fingerprints.

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: Methods, apparatus and computer program products implement embodiments of the present invention that include defining, in a storage system including receiving, by a storage system, a storage request, and identifying, based on the storage request, one or more storage management units. For each of the storage management units, a master partition table having multiple master entries and one or more backup partition tables is identified, each of the backup partition tables having backup entries in a one-to-one-correspondence with the master entries. Upon detecting a failure in master partition table, one of the backup partition tables is configured as a replacement master partition table, essential metadata is used to calculate non-essential metadata in the replacement master partition table, and the calculated non-essential metadata is stored to the replacement master partition table.

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: Data reduction in a storage system comprises determining attributes of data for storage in the storage system and determining expected data reduction effectiveness for the data based on said attributes. Said effectiveness indicates the benefit that data reduction is expected to provide for the data based on said attributes. The data reduction further comprises applying data reduction to the data based on the expected data reduction effectiveness and performance impact, to improve resource usage efficiency.

Abstract: Various embodiments for identifying data in a data deduplication system, by a processor device, are provided. In one embodiment, a method comprises efficiently identifying duplicate data in the data deduplication system by identifying fingerprint matches using a direct inter-region fingerprint lookup to search for the fingerprint matches in at least one of a plurality of metadata regions, the direct inter-region fingerprint lookup supplementing a central fingerprint index.

Abstract: Data reduction in a storage system comprises determining attributes of data for storage in the storage system and determining expected data reduction effectiveness for the data based on said attributes. Said effectiveness indicates the benefit that data reduction is expected to provide for the data based on said attributes. The data reduction further comprises applying data reduction to the data based on the expected data reduction effectiveness and performance impact, to improve resource usage efficiency.

Abstract: Methods, apparatus and computer program products implement embodiments of the present invention that include defining, in a storage system including receiving, by a processor, metadata describing a first cache configured as a master cache having non-destaged data, and defining, using the received metadata, a second cache configured as a backup cache for the master cache. Subsequent to defining the second cache, the non-destaged data is retrieved from the first cache, and the non-destaged data is stored to the second cache.

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: Methods, apparatus and computer program products implement embodiments of the present invention that include defining, in a storage system including multiple storage devices, multiple redundant array of independent disks (RAID) configurations for data stored on the storage devices. A first one of the multiple RAID configurations is assigned to a first entry in a partition table having multiple entries. Assigning the first one of the multiple RAID configurations to the first entry in the partition table comprises modifying an existing RAID configuration for the first entry. Data referenced by the existing RAID configuration is migrated to the modified RAID configuration.

Abstract: Methods, apparatus and computer program products implement embodiments of the present invention that include identifying non-destaged first data in a write cache. Upon detecting second data in a master read cache, the second data is pinned to the master and one or more backup read caches. Using the first data stored in the write cache and the second data stored in the master read cache, one or more parity values are calculated, and the first data and the one or more parity values are destaged.

Abstract: Embodiments of the invention relate to a storage system organized into a hierarchy of storage tiers, with at least one tier reflecting a high performance tier and at least one tier reflecting a lower performance tier. The high performance tier has a capacity restriction and has a limited quantity of blocks and pages may be placed in the tier. Assessments are conducted and a preferred selection of blocks and pages are recommended for placement; the recommendation is based on the assessment. The recommendation is converted to an actual placement, resulting in placement of at least one block, an in one embodiment at least one page, in the high performance tier.

Abstract: Embodiments relate to sub-block input/output (I/O) commands in a computer storage device. An aspect includes receiving a plurality of I/O commands on an I/O interface of the computer storage device, the computer storage device comprising a byte stream buffer module comprising a plurality of byte stream buffers, a block buffer module comprising a plurality of block buffers, and a main storage comprising a plurality of fixed-size storage blocks. Another aspect includes processing the plurality of I/O commands by the computer storage device. Another aspect includes a block write command comprising a command to write an amount of write data having a size equal to one of the plurality of a fixed-size storage block. Another aspect includes a sub-block write command comprising a command to write an amount of write data having a size that is less than a size of a fixed-size storage block.

Abstract: A computer-implemented method for determining performance shortfall in a storage system includes recording a log of I/O operations of a storage system, wherein each I/O operation includes associated operational parameters. The method prepares the storage system to perform a replay of a performance shortfall that occurred during a specified time frame. The method performs the replay on the storage system based at least on the log of I/O operations and the I/O operations' associated operational parameters for the specified time frame. The method identifies a cause for the performance shortfall during the specified time frame based at least on the difference between I/O performance measures of the replay and I/O performance measures for the specified time frame.

Abstract: Data placement for loss protection in a storage system 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, and a balancing policy for balancing placement of the storage symbols for each volume among physical storage containers. A first logical compartment of the multiple logical compartments is data loss independent with respect to a second logical compartment.

Abstract: Provided are a method, system, and article of manufacture for authenticating a processing system accessing a resource. An association of processing system identifiers with resources, including a first and second resources, is maintained. A request from a requesting processing system in a host is received for use of a first resource that provides access to a second resource, wherein the request is generated by processing system software and wherein the request further includes a submitted processing system identifier included in the request by host hardware in the host. A determination is made as to whether the submitted processing system identifier is one of the processing system identifiers associated with the first and second resources. The requesting processing system is provided access to the first resource that the processing system uses to access the second resource.

Abstract: Methods, apparatus and computer program products implement embodiments of the present invention that enable a computer to receive a request to allocate one or more logical regions to a logical volume, and to verify, in response to the request, an availability on one or more storage devices of a number of physical regions corresponding to the one or more requested logical regions. In response to the verification, the one or more logical regions can be activated for write operations to a cache, so that any data written to the logical regions is stored to the cache. Subsequent to activating the one or more logical regions, one or more actual physical regions can be allocated to the logical volume. Upon allocating the one or more actual physical regions, any data stored in the cache can be destaged to the one or more actual physical regions.