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: computing a fingerprint of data included in a write request; 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 deduplicating storage system includes a processor and logic integrated with and/or executable by the processor. The logic is configured to cause the processor to perform a method which includes: computing a fingerprint of a data chunk, and determining whether a short term dictionary corresponding to the namespace comprises an entry corresponding to the fingerprint. In response to determining the short term dictionary does not comprise the entry, a determination is made whether a long term dictionary corresponding to the namespace comprises the entry. In response to determining the long term dictionary comprises the entry: the data chunk is written to the data store in the deduplicating manner, and the short term dictionary is repopulated with the entry. Moreover, in response to determining the long term dictionary does not comprise the entry, the data chunk is written to the data store in a non-deduplicating manner.

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: In one embodiment, a deduplicating storage system includes a processor and logic integrated with and/or executable by the processor. The logic is configured to cause the processor to perform a method which includes: computing a fingerprint of a data chunk, and determining whether a short term dictionary corresponding to the namespace comprises an entry corresponding to the fingerprint. In response to determining the short term dictionary does not comprise the entry, a determination is made whether a long term dictionary corresponding to the namespace comprises the entry. In response to determining the long term dictionary comprises the entry: the data chunk is written to the data store in the deduplicating manner, and the short term dictionary is repopulated with the entry. Moreover, in response to determining the long term dictionary does not comprise the entry, the data chunk is written to the data store in a non-deduplicating manner.

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: computing a fingerprint of data included in a write request; 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: 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-implemented method for performing deduplication in conjunction with random read and write operations across a namespace that is divided into a plurality of disjoint regions is disclosed. The method includes: maintaining a metadata structure for each of the plurality of disjoint regions via the respective region manager, each metadata structure comprising metadata indicating a physical storage location of one or more data chunks associated with the respective region; and performing a deduplicated write operation. The deduplicated write operation includes: determining whether the disjoint regions comprise a second data chunk identical in content to a first data chunk; and in response to determining one or more of the plurality of disjoint regions other than the first region includes the second data chunk, establishing a reference from the first data chunk to the second data chunk. Corresponding systems and computer program products are also disclosed.

Abstract: Embodiments relate to host-side cache migration. An aspect is a method that includes determining pre-fetch hints associated with a source cache that is local to a source host machine. The source cache includes pages of cache data for a virtual machine. The pre-fetch hints are sent to a pre-fetch planner to create a pre-fetch plan. The pre-fetch hints are sent based on migration of the virtual machine to a target host machine including a target cache that is local. At the source host machine, a cache migration request is received based on the pre-fetch plan. A first subset of the pages is sent from the source cache through a host-to-host communication channel to the target cache based on the cache migration request. A second subset of the pages is sent from the source cache through a host-storage communication channel to a shared storage to be relayed to the target cache.

Abstract: Embodiments of the invention relate to storage systems, and for recording event records into a log. Different statistics may be tallied from the log, with the different statistics generating different statistical measurements. The aspect of processing of I/O and preparation of statistical measurements are separated, thereby enabling data structures and algorithms which would not be considered feasible for use as part of I/O processing, because they may compromise the performance or other essential characteristic of I/O processing, to be employed.

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: Embodiments relate to avoiding out-of-space conditions in storage controllers operating with efficiency capabilities between virtual space in a data container and real space in a storage container. Both the real space and the virtual space are monitored. The real space usage is compared to a threshold to provide information about occupancy of the real space. A virtual size of the virtual object is adjusted responsive to the real space usage meeting or exceeding the threshold.

Abstract: In one embodiment, a computer-implemented method for performing deduplication in conjunction with random read and write operations across a namespace that is divided into a plurality of disjoint regions is disclosed. The method includes: maintaining a metadata structure for each of the plurality of disjoint regions via the respective region manager, each metadata structure comprising metadata indicating a physical storage location of one or more data chunks associated with the respective region; and performing a deduplicated write operation. The deduplicated write operation includes: determining whether the disjoint regions comprise a second data chunk identical in content to a first data chunk; and in response to determining one or more of the plurality of disjoint regions other than the first region includes the second data chunk, establishing a reference from the first data chunk to the second data chunk. Corresponding systems and computer program products are also disclosed.

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: 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: 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: 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 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: Embodiments relate to avoiding out-of-space conditions in storage controllers operating with efficiency capabilities between virtual space in a data container and real space in a storage container. Both the real space and the virtual space are monitored. The real space usage is compared to a threshold to provide information about occupancy of the real space. A virtual size of the virtual object is adjusted responsive to the real space usage meeting or exceeding the threshold.

Abstract: Embodiments of the invention relates to avoiding out-of-space conditions in storage controllers operating with efficiency capabilities between virtual space in a data container and real space in a storage container. Both the real space and the virtual space are monitored and their respective usage is compared to provide information about occupancy of the real space to the virtual space. Usage of the containers is balanced by employing a virtual file associated with a reserved portion of free capacity in the virtual space.